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Mathematical Appendix

Authors
Affiliations
Hunter College and The Graduate Center, City University of New York
Hunter College and The Graduate Center, City University of New York

A Model of Enclosures: Coordination, Conflict, and Efficiency in the Transformation of Land Property Rights

Matthew J. Baker and Jonathan Conning Hunter College and the Graduate Center, City University of New York


Overview

This online appendix provides complete mathematical derivations for all numbered equations in the main paper. The appendix is organized to mirror the structure of the paper, presenting step-by-step derivations, highlighting key mathematical techniques, and referencing computational implementations for verification.

Contents:

Notation

The paper’s symbol table, with a column added for the corresponding name in the enclose package — so a symbol here can be traced to the code that computes it.

SymbolMeaningEffect of an increaseKey thresholdsIn code
θ\thetaTFP gain on enclosed land (θ=Ae/Ac\theta = A_e/A_c)Raises the return to enclosing; crossing θHμ\theta_H^\mu switches decisions from complements to substitutes, and the risk from over- to under-enclosureθH=1/α\theta_H = 1/\alpha; θ=1\theta = 1 separates progressive from regressive enclosureth
AABaseline TFPEnters only as c/Ac/A: shifts every locus down by the same vertical distance(absent — see below)
α\alphaLabor share (Cobb–Douglas)Lowers θH=1/α\theta_H = 1/\alpha, shrinking the race-prone complements regionalp, default loci.ALP
lˉ=Lˉ/Tˉ\bar l = \bar L/\bar TPopulation densitySmooth tet_e \uparrow if θ>θH\theta > \theta_H; a jump at lˉggd\bar l_{gg}^d if θ<θH\theta < \theta_HLoci lˉ01,lˉ11,lˉ0d,lˉ1d,lˉggd,lˉs,\bar l_0^1, \bar l_1^1, \bar l_0^d, \bar l_1^d, \bar l_{gg}^d, \bar l^s, \dotslbar; loci return lnlˉ\ln\bar l
ccEnclosure cost per unit landShifts every locus up by the same vertical distance — geometrically identical to the economy’s point moving downEnters all loci as c/Ac/A, each scaling as (c/A)1/α(c/A)^{1/\alpha}c, default loci.C
te, let_e,\ l_eShares of land, labor in the enclosed sectorte, model.le
μ[0,1]\mu \in [0,1]Community capacity to regulate commons accessShrinks labor misallocation and moves θHμ\theta_H^\mu left toward 1; under-enclosure shrinks, but over-enclosure expands if τ=0\tau = 0μ=1\mu=1: no misallocation; θHμ=1αμ1αα\theta_H^\mu = \frac{1}{\alpha} - \mu\frac{1-\alpha}{\alpha}mu
τ[0,1]\tau \in [0,1]Compensation/resistance power of customary usersRaises the density needed before enclosure pays; over-enclosure shrinks, under-enclosure expandsτ=1\tau=1: “trade”; τ=0\tau=0: “raid”tau

Also used in this appendix, beyond the paper’s table:

SymbolMeaningIn code
Λμ=(αθ/Aμ)1/(1α)\Lambda_\mu = \left(\alpha\theta/A_\mu\right)^{1/(1-\alpha)}Enclosed-to-commons labor intensity; Λo=θ1/(1α)\Lambda_o = \theta^{1/(1-\alpha)} is the planner’smodel.Lambda(th, alp, mu), loci.lam_mu
Aμ=1μ(1α)A_\mu = 1-\mu(1-\alpha)Share of the commons average product labor retains, eq. (37)manufacturing.commons_wedge
θHμ\theta_H^\muWhere Λμ=1\Lambda_\mu = 1: enclosure switches labor-extensive to labor-intensivemodel.theta_H(alp, mu)
θτ=τ1α(Aμ/α)α\theta_\tau = \tau^{1-\alpha}(A_\mu/\alpha)^{\alpha}Below it enclosure earns less than the compensation owed, at any density — eq. (27b)loci.theta_tau(alp, mu, tau)
Tˉ, Lˉ, Kˉ\bar T,\ \bar L,\ \bar KTotal land, labor, capital endowments; tˉ=Tˉ/Lˉ\bar t = \bar T/\bar L, kˉ=Kˉ/Lˉ\bar k = \bar K/\bar Ltbar, lbar, kb
lc, lml_c,\ l_mLabor shares in the commons and in manufacturing (§6.4)manufacturing.labor_share
β(0,1)\beta \in (0,1), p>0p > 0Manufacturing labor share and relative price (§6.4)b, p

Section 3: Benchmark Model

3.1 Technology and Resources

We begin by establishing the production technology and key relationships. Production in both enclosed and unenclosed sectors follows Cobb-Douglas technology:

Unenclosed sector:

F(Tc,Lc)=Tc1αLcαF(T_c, L_c) = T_c^{1-\alpha}L_c^\alpha

Enclosed sector:

G(Te,Le)=θTe1αLeαG(T_e, L_e) = \theta \cdot T_e^{1-\alpha}L_e^\alpha

where θ1\theta \geq 1 captures potential productivity gains from enclosure.

Key Property: Homogeneity of Production

For Cobb-Douglas production with constant returns to scale, we have the useful property:

F(teTˉ,leLˉ)=(teTˉ)1α(leLˉ)α=te1αTˉ1αleαLˉα=F(te,le)F(Tˉ,Lˉ)F(t_e\bar{T}, l_e\bar{L}) = (t_e\bar{T})^{1-\alpha}(l_e\bar{L})^\alpha = t_e^{1-\alpha}\bar{T}^{1-\alpha} \cdot l_e^\alpha\bar{L}^\alpha = F(t_e, l_e) \cdot F(\bar{T}, \bar{L})

This allows us to factor out the scale F(Tˉ,Lˉ)F(\bar{T}, \bar{L}) and work with shares.

Potential Output per Unit Land

We define:

Alˉα=AF(Tˉ,Lˉ)Tˉ=ATˉ1αLˉαTˉ=A(LˉTˉ)α=AlˉαA\bar{l}^\alpha = A \cdot \frac{F(\bar{T}, \bar{L})}{\bar{T}} = A \cdot \frac{\bar{T}^{1-\alpha}\bar{L}^\alpha}{\bar{T}} = A\left(\frac{\bar{L}}{\bar{T}}\right)^\alpha = A\bar{l}^\alpha

This represents potential output per unit land using the base technology, and serves as a convenient normalization throughout.


3.2 First-Best Labor Allocation and Enclosure

Equation (1): Social Planner’s Objective

The social planner maximizes total output net of enclosure costs:

maxte,leA[θF(teTˉ,leLˉ)+F((1te)Tˉ,(1le)Lˉ)]cteTˉ(1)\max_{t_e, l_e} A\left[\theta F(t_e\bar{T}, l_e\bar{L}) + F((1-t_e)\bar{T}, (1-l_e)\bar{L})\right] - ct_e\bar{T} \qquad (1)

Derivation:


Equation (2): Normalized Planner’s Objective

Using the homogeneity property, we can rewrite (1) as:

maxte,le[θF(te,le)+F(1te,1le)]Alˉαcte(2)\max_{t_e, l_e} \left[\theta F(t_e, l_e) + F(1-t_e, 1-l_e)\right] \cdot A\bar{l}^\alpha - c \cdot t_e \qquad (2)

Derivation: Starting from (1):

A[θF(teTˉ,leLˉ)+F((1te)Tˉ,(1le)Lˉ)]cteTˉA\left[\theta F(t_e\bar{T}, l_e\bar{L}) + F((1-t_e)\bar{T}, (1-l_e)\bar{L})\right] - ct_e\bar{T}

Factor out F(Tˉ,Lˉ)F(\bar{T}, \bar{L}) from each production term:

=A[θF(te,le)F(Tˉ,Lˉ)+F(1te,1le)F(Tˉ,Lˉ)]cteTˉ= A\left[\theta F(t_e, l_e) \cdot F(\bar{T}, \bar{L}) + F(1-t_e, 1-l_e) \cdot F(\bar{T}, \bar{L})\right] - ct_e\bar{T}
=AF(Tˉ,Lˉ)[θF(te,le)+F(1te,1le)]cteTˉ= A F(\bar{T}, \bar{L})\left[\theta F(t_e, l_e) + F(1-t_e, 1-l_e)\right] - ct_e\bar{T}

Divide the objective by Tˉ\bar{T} (which doesn’t affect the maximizing choices):

=AF(Tˉ,Lˉ)Tˉ[θF(te,le)+F(1te,1le)]cte= \frac{AF(\bar{T}, \bar{L})}{\bar{T}}\left[\theta F(t_e, l_e) + F(1-t_e, 1-l_e)\right] - ct_e
=Alˉα[θF(te,le)+F(1te,1le)]cte= A\bar{l}^\alpha\left[\theta F(t_e, l_e) + F(1-t_e, 1-l_e)\right] - ct_e

This formulation isolates the allocation problem (choosing te,let_e, l_e) from scale effects.


Equation (3): Marginal Product Equalization

The first-order condition with respect to lel_e yields:

θαA(tele)1α=αA(1te1le)1α(3)\theta \alpha A\left(\frac{t_e}{l_e}\right)^{1-\alpha} = \alpha A\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha} \qquad (3)

Derivation: From (2), the objective is:

[θte1αleα+(1te)1α(1le)α]Alˉαcte\left[\theta t_e^{1-\alpha}l_e^\alpha + (1-t_e)^{1-\alpha}(1-l_e)^\alpha\right] \cdot A\bar{l}^\alpha - ct_e

Take the derivative with respect to lel_e:

le[θte1αleα+(1te)1α(1le)α]Alˉα=0\frac{\partial}{\partial l_e}\left[\theta t_e^{1-\alpha}l_e^\alpha + (1-t_e)^{1-\alpha}(1-l_e)^\alpha\right] \cdot A\bar{l}^\alpha = 0

Apply the power rule:

[θte1ααleα1+(1te)1αα(1le)α1(1)]Alˉα=0\left[\theta t_e^{1-\alpha} \cdot \alpha l_e^{\alpha-1} + (1-t_e)^{1-\alpha} \cdot \alpha(1-l_e)^{\alpha-1} \cdot (-1)\right] \cdot A\bar{l}^\alpha = 0

Simplify:

θαte1αleα1=α(1te)1α(1le)α1\theta \alpha t_e^{1-\alpha}l_e^{\alpha-1} = \alpha(1-t_e)^{1-\alpha}(1-l_e)^{\alpha-1}

Divide both sides by α\alpha and rearrange:

θte1αleα1=(1te)1α(1le)α1\theta t_e^{1-\alpha}l_e^{\alpha-1} = (1-t_e)^{1-\alpha}(1-l_e)^{\alpha-1}

Rewrite as:

θ(tele)1α=(1te1le)1α\theta \left(\frac{t_e}{l_e}\right)^{1-\alpha} = \left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha}

This states that the planner equalizes the marginal product of labor across sectors.


Equation (4): First-Best Labor Allocation Function

Solving (3) for lel_e as a function of tet_e:

le1(te)=θ11αte1+(θ11α1)te(4)l_e^1(t_e) = \frac{\theta^{\frac{1}{1-\alpha}}t_e}{1+\left(\theta^{\frac{1}{1-\alpha}}-1\right)t_e} \qquad (4)

Derivation: Starting from (3):

θ(tele)1α=(1te1le)1α\theta \left(\frac{t_e}{l_e}\right)^{1-\alpha} = \left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha}

Take both sides to the power 11α\frac{1}{1-\alpha}:

θ11αtele=1te1le\theta^{\frac{1}{1-\alpha}} \cdot \frac{t_e}{l_e} = \frac{1-t_e}{1-l_e}

Define Λo=θ11α\Lambda_o = \theta^{\frac{1}{1-\alpha}} for convenience. Then:

Λotele=1te1le\Lambda_o \cdot \frac{t_e}{l_e} = \frac{1-t_e}{1-l_e}

Cross-multiply:

Λote(1le)=le(1te)\Lambda_o t_e(1-l_e) = l_e(1-t_e)

Expand:

ΛoteΛotele=lelete\Lambda_o t_e - \Lambda_o t_e l_e = l_e - l_e t_e

Collect terms with lel_e on the left:

Λote=le+Λotelelete\Lambda_o t_e = l_e + \Lambda_o t_e l_e - l_e t_e
Λote=le(1+Λotete)\Lambda_o t_e = l_e(1 + \Lambda_o t_e - t_e)
Λote=le(1+(Λo1)te)\Lambda_o t_e = l_e(1 + (\Lambda_o - 1)t_e)

Solve for lel_e:

le=Λote1+(Λo1)tel_e = \frac{\Lambda_o t_e}{1+(\Lambda_o-1)t_e}

This is the planner’s optimal labor allocation function, showing how labor should be distributed for any given enclosure rate tet_e.


Equation (5): Simplified Planner’s Objective

Substituting le1(te)l_e^1(t_e) into the objective (2) yields:

maxtez1(te)cte\max_{t_e} z_1(t_e) - c \cdot t_e

where

z1(te)=[1+(θ11α1)te]1αAlˉα(5)z_1(t_e) = \left[1+\left(\theta^{\frac{1}{1-\alpha}}-1\right)t_e\right]^{1-\alpha} \cdot A\bar{l}^\alpha \qquad (5)

Derivation: This is a crucial simplification. Starting from (2) with le=le1(te)=Λote1+(Λo1)tel_e = l_e^1(t_e) = \frac{\Lambda_o t_e}{1+(\Lambda_o-1)t_e}:

z1(te)=[θte1αleα+(1te)1α(1le)α]Alˉαz_1(t_e) = \left[\theta t_e^{1-\alpha}l_e^\alpha + (1-t_e)^{1-\alpha}(1-l_e)^\alpha\right] \cdot A\bar{l}^\alpha

Let’s break this into two terms: A=θte1αleαA = \theta t_e^{1-\alpha}l_e^\alpha and B=(1te)1α(1le)αB = (1-t_e)^{1-\alpha}(1-l_e)^\alpha.

Term A:

A=θte1α(Λote1+(Λo1)te)αA = \theta t_e^{1-\alpha}\left(\frac{\Lambda_o t_e}{1+(\Lambda_o-1)t_e}\right)^\alpha
=θte1α(Λote)α(1+(Λo1)te)α= \theta t_e^{1-\alpha} \cdot \frac{(\Lambda_o t_e)^\alpha}{(1+(\Lambda_o-1)t_e)^\alpha}
=θte1αteαΛoα(1+(Λo1)te)α= \theta \cdot \frac{t_e^{1-\alpha} \cdot t_e^\alpha \cdot \Lambda_o^\alpha}{(1+(\Lambda_o-1)t_e)^\alpha}
=θteΛoα(1+(Λo1)te)α= \theta \cdot \frac{t_e \cdot \Lambda_o^\alpha}{(1+(\Lambda_o-1)t_e)^\alpha}

Key Mathematical Trick: Note that θΛoα=θ(θ11α)α=θθα1α=θ1+α1α=θ1α+α1α=θ11α=Λo\theta \cdot \Lambda_o^\alpha = \theta \cdot (\theta^{\frac{1}{1-\alpha}})^\alpha = \theta \cdot \theta^{\frac{\alpha}{1-\alpha}} = \theta^{1+\frac{\alpha}{1-\alpha}} = \theta^{\frac{1-\alpha+\alpha}{1-\alpha}} = \theta^{\frac{1}{1-\alpha}} = \Lambda_o

Therefore:

A=Λote(1+(Λo1)te)αA = \frac{\Lambda_o t_e}{(1+(\Lambda_o-1)t_e)^\alpha}

Term B: First note that:

1le=1Λote1+(Λo1)te=1+(Λo1)teΛote1+(Λo1)te=1te1+(Λo1)te1-l_e = 1 - \frac{\Lambda_o t_e}{1+(\Lambda_o-1)t_e} = \frac{1+(\Lambda_o-1)t_e - \Lambda_o t_e}{1+(\Lambda_o-1)t_e} = \frac{1-t_e}{1+(\Lambda_o-1)t_e}

Thus:

B=(1te)1α(1te1+(Λo1)te)αB = (1-t_e)^{1-\alpha}\left(\frac{1-t_e}{1+(\Lambda_o-1)t_e}\right)^\alpha
=(1te)1α(1te)α(1+(Λo1)te)α= \frac{(1-t_e)^{1-\alpha}(1-t_e)^\alpha}{(1+(\Lambda_o-1)t_e)^\alpha}
=1te(1+(Λo1)te)α= \frac{1-t_e}{(1+(\Lambda_o-1)t_e)^\alpha}

Combining A and B:

A+B=Λote+(1te)(1+(Λo1)te)αA + B = \frac{\Lambda_o t_e + (1-t_e)}{(1+(\Lambda_o-1)t_e)^\alpha}
=1+(Λo1)te(1+(Λo1)te)α= \frac{1 + (\Lambda_o-1)t_e}{(1+(\Lambda_o-1)t_e)^\alpha}
=(1+(Λo1)te)1α= (1+(\Lambda_o-1)t_e)^{1-\alpha}

Therefore:

z1(te)=(1+(Λo1)te)1αAlˉαz_1(t_e) = (1+(\Lambda_o-1)t_e)^{1-\alpha} \cdot A\bar{l}^\alpha

This elegant closed form shows that output is increasing and concave in tet_e when θ>1\theta > 1 (so Λo>1\Lambda_o > 1).


Equation (6): No-Enclosure Threshold

The planner chooses no enclosure when:

z1(0)clˉ[1(1α)(θ11α1)cA]1α=lˉ01(θ)(6)z_1'(0) \leq c \Leftrightarrow \bar{l} \leq \left[\frac{1}{(1-\alpha)\left(\theta^{\frac{1}{1-\alpha}}-1\right)} \cdot \frac{c}{A}\right]^{\frac{1}{\alpha}} = \bar{l}_0^1(\theta) \qquad (6)

Derivation: First, compute z1(te)z_1'(t_e):

z1(te)=Alˉα(1+(Λo1)te)1αz_1(t_e) = A\bar{l}^\alpha \cdot (1+(\Lambda_o-1)t_e)^{1-\alpha}
z1(te)=Alˉα(1α)(1+(Λo1)te)α(Λo1)z_1'(t_e) = A\bar{l}^\alpha \cdot (1-\alpha)(1+(\Lambda_o-1)t_e)^{-\alpha} \cdot (\Lambda_o-1)
=(1α)(Λo1)Alˉα(1+(Λo1)te)α= (1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha \cdot (1+(\Lambda_o-1)t_e)^{-\alpha}

Evaluate at te=0t_e = 0:

z1(0)=(1α)(Λo1)Alˉαz_1'(0) = (1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha

For no enclosure to be optimal, we need z1(0)cz_1'(0) \leq c:

(1α)(Λo1)Alˉαc(1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha \leq c

Solve for lˉ\bar{l}:

lˉαc(1α)(Λo1)A\bar{l}^\alpha \leq \frac{c}{(1-\alpha)(\Lambda_o-1)A}
lˉ[c(1α)(Λo1)A]1α\bar{l} \leq \left[\frac{c}{(1-\alpha)(\Lambda_o-1)A}\right]^{\frac{1}{\alpha}}

Substituting Λo=θ11α\Lambda_o = \theta^{\frac{1}{1-\alpha}}:

lˉ01(θ)=[1(1α)(θ11α1)cA]1α\bar{l}_0^1(\theta) = \left[\frac{1}{(1-\alpha)(\theta^{\frac{1}{1-\alpha}}-1)} \cdot \frac{c}{A}\right]^{\frac{1}{\alpha}}

This defines a threshold population density below which enclosure is not worthwhile.


Equation (7): Full-Enclosure Threshold

The planner chooses full enclosure when:

z1(1)clˉθ11αlˉ01(θ)=lˉ11(θ)(7)z_1'(1) \geq c \Leftrightarrow \bar{l} \geq \theta^{\frac{1}{1-\alpha}} \cdot \bar{l}_0^1(\theta) = \bar{l}_1^1(\theta) \qquad (7)

Derivation: Evaluate z1(te)z_1'(t_e) at te=1t_e = 1:

z1(1)=(1α)(Λo1)Alˉα(1+(Λo1))αz_1'(1) = (1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha \cdot (1+(\Lambda_o-1))^{-\alpha}
=(1α)(Λo1)AlˉαΛoα= (1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha \cdot \Lambda_o^{-\alpha}

For full enclosure to be optimal, we need z1(1)cz_1'(1) \geq c:

(1α)(Λo1)AlˉαΛoαc(1-\alpha)(\Lambda_o-1) \cdot A\bar{l}^\alpha \cdot \Lambda_o^{-\alpha} \geq c
lˉαcΛoα(1α)(Λo1)A\bar{l}^\alpha \geq \frac{c \cdot \Lambda_o^\alpha}{(1-\alpha)(\Lambda_o-1)A}
lˉ[cΛoα(1α)(Λo1)A]1α\bar{l} \geq \left[\frac{c \cdot \Lambda_o^\alpha}{(1-\alpha)(\Lambda_o-1)A}\right]^{\frac{1}{\alpha}}

Note that this can be written as:

lˉ11=Λo[c(1α)(Λo1)A]1α=Λolˉ01=θ11αlˉ01(θ)\bar{l}_1^1 = \Lambda_o \cdot \left[\frac{c}{(1-\alpha)(\Lambda_o-1)A}\right]^{\frac{1}{\alpha}} = \Lambda_o \cdot \bar{l}_0^1 = \theta^{\frac{1}{1-\alpha}} \cdot \bar{l}_0^1(\theta)

This shows that the full enclosure threshold is exactly Λo\Lambda_o times the no-enclosure threshold.

Summary of First-Best: The planner chooses:

Socially efficient enclosure regions.

Figure 1:Socially efficient enclosure regions.


3.3 Decentralized Enclosure Processes

Equation (8): Average Product Decomposition

By Euler’s theorem for homogeneous functions:

APLc=MPLc+MPTcTcLc(8)AP_L^c = MP_L^c + MP_T^c \cdot \frac{T_c}{L_c} \qquad (8)

Derivation: For a homogeneous function of degree one (constant returns to scale), Euler’s theorem states:

F(T,L)=TFT+LFLF(T, L) = T \cdot F_T + L \cdot F_L

where FT=FTF_T = \frac{\partial F}{\partial T} and FL=FLF_L = \frac{\partial F}{\partial L}.

Divide both sides by LL:

F(T,L)L=TLFT+FL\frac{F(T,L)}{L} = \frac{T}{L} \cdot F_T + F_L

In other notation:

APL=MPL+MPTTLAP_L = MP_L + MP_T \cdot \frac{T}{L}

This decomposition is crucial: it shows that average product exceeds marginal product by the amount MPT(T/L)MP_T \cdot (T/L), which represents the possession rent that labor captures under open access when it must occupy land.


Equation (9): Labor Market Equilibrium (Decentralized)

Under open access to unenclosed land, labor equilibrium requires:

θαA(tele)1α=A(1te1le)1α(9)\theta \alpha A\left(\frac{t_e}{l_e}\right)^{1-\alpha} = A\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha} \qquad (9)

Derivation: In the enclosed sector, competitive firms pay labor its marginal product:

we=MPLe=θαA(tele)1αlˉαw_e = MP_L^e = \theta \alpha A\left(\frac{t_e}{l_e}\right)^{1-\alpha} \cdot \bar{l}^\alpha

In the unenclosed (common) sector under open access, labor captures the average product (not marginal product) because workers must possess land to produce:

wc=APLc=AF(1te,1le)1lelˉα=A(1te1le)1αlˉαw_c = AP_L^c = A\frac{F(1-t_e, 1-l_e)}{1-l_e} \cdot \bar{l}^\alpha = A\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha} \cdot \bar{l}^\alpha

Labor mobility requires we=wcw_e = w_c:

θαA(tele)1αlˉα=A(1te1le)1αlˉα\theta \alpha A\left(\frac{t_e}{l_e}\right)^{1-\alpha} \cdot \bar{l}^\alpha = A\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha} \cdot \bar{l}^\alpha

Cancel AlˉαA\bar{l}^\alpha to get (9).

The key difference from (3) is the α\alpha multiplier on the left-hand side, reflecting that labor earns only its marginal product in the enclosed sector but captures the average product in the commons.


Equation (10): Labor Reaction Function (Decentralized)

Solving (9) for lel_e yields:

le0(te)=(αθ)11αte1+((αθ)11α1)te(10)l_e^0(t_e) = \frac{(\alpha\theta)^{\frac{1}{1-\alpha}}t_e}{1+\left((\alpha\theta)^{\frac{1}{1-\alpha}}-1\right)t_e} \qquad (10)

Derivation: From (9):

θα(tele)1α=(1te1le)1α\theta \alpha \left(\frac{t_e}{l_e}\right)^{1-\alpha} = \left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha}

Raise both sides to power 11α\frac{1}{1-\alpha}:

(αθ)11αtele=1te1le(\alpha\theta)^{\frac{1}{1-\alpha}} \cdot \frac{t_e}{l_e} = \frac{1-t_e}{1-l_e}

Define Λ=(αθ)11α\Lambda = (\alpha\theta)^{\frac{1}{1-\alpha}} (note: different from Λo=θ11α\Lambda_o = \theta^{\frac{1}{1-\alpha}}!).

Then following identical algebraic steps to equation (4):

Λtele=1te1le\Lambda \cdot \frac{t_e}{l_e} = \frac{1-t_e}{1-l_e}

Cross-multiply and solve:

le=Λte1+(Λ1)tel_e = \frac{\Lambda t_e}{1+(\Lambda-1)t_e}

Critical Distinction: Under decentralized enclosure with open-access commons, Λ=(αθ)11α\Lambda = (\alpha\theta)^{\frac{1}{1-\alpha}} whereas the planner uses Λo=θ11α\Lambda_o = \theta^{\frac{1}{1-\alpha}}. Since α<1\alpha < 1, we have Λ<Λo\Lambda < \Lambda_o, meaning the decentralized economy allocates less labor to enclosed land than is socially optimal (for any given tet_e). This is the labor misallocation at the heart of the inefficiency.


Equation (11): Private Return to Enclosure (General Form)

A private encloser’s return is:

r(te)=θAFT(teTˉ,le0(te)Lˉ)(11)r(t_e) = \theta \cdot AF_T(t_e\bar{T}, l_e^0(t_e)\bar{L}) \qquad (11)

Derivation: An encloser captures the marginal product of land in the enclosed sector. For Cobb-Douglas:

FT=(1α)F(T,L)T=(1α)TαLαF_T = (1-\alpha) \cdot \frac{F(T,L)}{T} = (1-\alpha)T^{-\alpha}L^\alpha

Therefore:

r(te)=θA(1α)(teTˉ)α(le0(te)Lˉ)αr(t_e) = \theta A(1-\alpha)(t_e\bar{T})^{-\alpha}(l_e^0(t_e)\bar{L})^\alpha
=θA(1α)teαTˉαleαLˉα= \theta A(1-\alpha) \cdot t_e^{-\alpha}\bar{T}^{-\alpha} \cdot l_e^\alpha\bar{L}^\alpha
=θA(1α)(lete)αlˉα= \theta A(1-\alpha) \cdot \left(\frac{l_e}{t_e}\right)^\alpha \cdot \bar{l}^\alpha

This is the rental rate per unit enclosed land, which depends on the labor intensity le/tel_e/t_e.


Equation (12): Private Return to Enclosure (Closed Form)

Substituting le0(te)l_e^0(t_e) from (10):

r(te)=θ(1α)Alˉα((αθ)11α1+((αθ)11α1)te)α(12)r(t_e) = \theta(1-\alpha)A\bar{l}^\alpha \cdot \left(\frac{(\alpha\theta)^{\frac{1}{1-\alpha}}}{1+\left((\alpha\theta)^{\frac{1}{1-\alpha}}-1\right)t_e}\right)^\alpha \qquad (12)

Derivation: From (11):

r(te)=θA(1α)(le0(te)te)αlˉαr(t_e) = \theta A(1-\alpha) \cdot \left(\frac{l_e^0(t_e)}{t_e}\right)^\alpha \cdot \bar{l}^\alpha

From (10), we have:

le0(te)te=Λ1+(Λ1)te\frac{l_e^0(t_e)}{t_e} = \frac{\Lambda}{1+(\Lambda-1)t_e}

where Λ=(αθ)11α\Lambda = (\alpha\theta)^{\frac{1}{1-\alpha}}.

Substitute:

r(te)=θA(1α)(Λ1+(Λ1)te)αlˉαr(t_e) = \theta A(1-\alpha) \cdot \left(\frac{\Lambda}{1+(\Lambda-1)t_e}\right)^\alpha \cdot \bar{l}^\alpha

Alternative form using mathematical trick: Note that θΛα=θ[(αθ)11α]α=θ(αθ)α1α\theta \cdot \Lambda^\alpha = \theta \cdot [(\alpha\theta)^{\frac{1}{1-\alpha}}]^\alpha = \theta \cdot (\alpha\theta)^{\frac{\alpha}{1-\alpha}}

=θ1+α1ααα1α=θ11ααα1α= \theta^{1+\frac{\alpha}{1-\alpha}} \cdot \alpha^{\frac{\alpha}{1-\alpha}} = \theta^{\frac{1}{1-\alpha}} \cdot \alpha^{\frac{\alpha}{1-\alpha}}

Actually, more directly:

θΛα=θ(αθ)α1α=αα1αθ1+α1α=αα1αθ11α\theta \cdot \Lambda^\alpha = \theta \cdot (\alpha\theta)^{\frac{\alpha}{1-\alpha}} = \alpha^{\frac{\alpha}{1-\alpha}} \cdot \theta^{1+\frac{\alpha}{1-\alpha}} = \alpha^{\frac{\alpha}{1-\alpha}} \cdot \theta^{\frac{1}{1-\alpha}}
=1ααα1α+1θ11α=1αα11αθ11α=Λα= \frac{1}{\alpha} \cdot \alpha^{\frac{\alpha}{1-\alpha}+1} \cdot \theta^{\frac{1}{1-\alpha}} = \frac{1}{\alpha} \cdot \alpha^{\frac{1}{1-\alpha}} \cdot \theta^{\frac{1}{1-\alpha}} = \frac{\Lambda}{\alpha}

So we can write:

r(te)=(1α)AlˉαΛαΛα1(1+(Λ1)te)αr(t_e) = (1-\alpha)A\bar{l}^\alpha \cdot \frac{\Lambda}{\alpha} \cdot \frac{\Lambda^{\alpha-1}}{(1+(\Lambda-1)t_e)^\alpha}

This simplifies to the form in (12).

Key Properties:


Equation (13): No-Enclosure Threshold (Decentralized)

Private enclosers begin enclosing when:

r(0)clˉ1(αθ)11α[cθA(1α)]1α=lˉ0d(13)r(0) \geq c \Leftrightarrow \bar{l} \geq \frac{1}{(\alpha\theta)^{\frac{1}{1-\alpha}}} \left[\frac{c}{\theta A(1-\alpha)}\right]^{\frac{1}{\alpha}} = \bar{l}_0^d \qquad (13)

Derivation: Evaluate r(te)r(t_e) at te=0t_e = 0:

r(0)=θ(1α)AlˉαΛαr(0) = \theta(1-\alpha)A\bar{l}^\alpha \cdot \Lambda^\alpha

where Λ=(αθ)11α\Lambda = (\alpha\theta)^{\frac{1}{1-\alpha}}.

Set r(0)=cr(0) = c:

θ(1α)AlˉαΛα=c\theta(1-\alpha)A\bar{l}^\alpha \cdot \Lambda^\alpha = c

Solve for lˉ\bar{l}:

lˉα=cθ(1α)AΛα\bar{l}^\alpha = \frac{c}{\theta(1-\alpha)A \cdot \Lambda^\alpha}
lˉ=[cθ(1α)AΛα]1α\bar{l} = \left[\frac{c}{\theta(1-\alpha)A \cdot \Lambda^\alpha}\right]^{\frac{1}{\alpha}}
=Λ1[cθ(1α)A]1α= \Lambda^{-1} \cdot \left[\frac{c}{\theta(1-\alpha)A}\right]^{\frac{1}{\alpha}}
=1(αθ)11α[cθ(1α)A]1α= \frac{1}{(\alpha\theta)^{\frac{1}{1-\alpha}}} \left[\frac{c}{\theta(1-\alpha)A}\right]^{\frac{1}{\alpha}}

Equation (14): Full-Enclosure Threshold (Decentralized)

Private enclosers fully enclose when:

r(1)clˉ[cθA(1α)]1α=lˉ1d(14)r(1) \geq c \Leftrightarrow \bar{l} \geq \left[\frac{c}{\theta A(1-\alpha)}\right]^{\frac{1}{\alpha}} = \bar{l}_1^d \qquad (14)

Derivation: Evaluate r(te)r(t_e) at te=1t_e = 1:

r(1)=θ(1α)Alˉα(Λ1+(Λ1))α=θ(1α)AlˉαΛαΛα=θ(1α)Alˉαr(1) = \theta(1-\alpha)A\bar{l}^\alpha \cdot \left(\frac{\Lambda}{1+(\Lambda-1)}\right)^\alpha = \theta(1-\alpha)A\bar{l}^\alpha \cdot \frac{\Lambda^\alpha}{\Lambda^\alpha} = \theta(1-\alpha)A\bar{l}^\alpha

Set r(1)=cr(1) = c:

θ(1α)Alˉα=c\theta(1-\alpha)A\bar{l}^\alpha = c
lˉ=[cθ(1α)A]1α\bar{l} = \left[\frac{c}{\theta(1-\alpha)A}\right]^{\frac{1}{\alpha}}

Note: lˉ1d=Λlˉ0d\bar{l}_1^d = \Lambda \cdot \bar{l}_0^d, similar to the first-best relationship.

Decentralized enclosure regions, including the multiplicity region.

Figure 2:Decentralized enclosure regions, including the multiplicity region.


Equation (15): Global Games Threshold (Risk-Dominant Equilibrium)

In the multiplicity region where θ<θH\theta < \theta_H, the unique risk-dominant equilibrium involves full enclosure when:

E[r(te)c]0lˉlˉggd(15)E[r(t_e) - c] \geq 0 \Leftrightarrow \bar{l} \geq \bar{l}_{gg}^d \qquad (15)

Derivation: The global games refinement (Morris and Shin 2003) selects the equilibrium where the expected return to enclosure equals the cost:

01r(te)dte=c\int_0^1 r(t_e) dt_e = c

Substituting r(te)r(t_e) from (12):

01θ(1α)Alˉα(Λ1+(Λ1)te)αdte=c\int_0^1 \theta(1-\alpha)A\bar{l}^\alpha \cdot \left(\frac{\Lambda}{1+(\Lambda-1)t_e}\right)^\alpha dt_e = c

Only the bracket depends on tet_e. The substitution u=1+(Λ1)teu = 1+(\Lambda-1)t_e reduces the integral to a power rule:

01(1+(Λ1)te)αdte=1Λ11Λuαdu=Λ1α1(1α)(Λ1)\int_0^1\left(1+(\Lambda-1)t_e\right)^{-\alpha}dt_e = \frac{1}{\Lambda-1}\int_1^{\Lambda}u^{-\alpha}\,du = \frac{\Lambda^{1-\alpha}-1}{(1-\alpha)(\Lambda-1)}

The factor (1α)(1-\alpha) cancels, and solving for population density gives the threshold in closed form:

lˉggd=[(c/A)(Λ1)θΛα(Λ1α1)]1α\bar{l}_{gg}^d = \left[\frac{(c/A)\left(\Lambda-1\right)} {\theta\Lambda^{\alpha}\left(\Lambda^{1-\alpha}-1\right)}\right]^{\frac{1}{\alpha}}

Since Λ1α=αθ\Lambda^{1-\alpha} = \alpha\theta by construction of Λ\Lambda, this is equivalently

lˉggd=[(c/A)(1Λ)θΛα(1αθ)]1α\bar{l}_{gg}^d = \left[\frac{(c/A)(1-\Lambda)}{\theta\Lambda^{\alpha}\,(1-\alpha\theta)}\right]^{\frac{1}{\alpha}}

which is the form used in the code. In the multiplicity region Λ<1\Lambda<1 and αθ<1\alpha\theta<1, so both the numerator and the denominator are positive.

Note: No special functions are needed — the integrand is a power of a linear function of tet_e. (Earlier versions of this appendix stated that the evaluation involves a beta function and requires numerical integration. Both were incorrect; the closed form above is elementary, and is what the accompanying code has always used.)

[End of Section 3]


Section 4: Social Efficiency of Private Enclosure Decisions

4.1 Are Decentralized Enclosures Second-Best?

We now ask whether decentralized enclosure decisions are at least “second-best” efficient—that is, optimal given the constraint that labor is misallocated due to open access. A second-best (or constrained) planner respects the labor allocation le0(te)l_e^0(t_e) that emerges from decentralized labor markets but can control the enclosure rate tet_e.

Equation (16): Second-Best Planner’s Objective

The second-best planner maximizes:

z0(te)=[θF(te,le0(te))+F(1te,1le0(te))]Alˉα(16)z_0(t_e) = \left[\theta F(t_e, l_e^0(t_e)) + F(1-t_e, 1-l_e^0(t_e))\right] \cdot A\bar{l}^\alpha \qquad (16)

subject to the constraint that labor allocation follows le0(te)l_e^0(t_e) from equation (10), not the first-best le1(te)l_e^1(t_e).

Comparison to First-Best:

Since Λ<Λo\Lambda < \Lambda_o, the second-best involves labor misallocation toward the unenclosed sector.


Equation (17): Second-Best Objective (Closed Form)

Substituting le0(te)l_e^0(t_e) yields:

z0(te)=lˉαθ(αθ)α1αte+(1te)(1+((αθ)11α1)te)α(17)z_0(t_e) = \bar{l}^\alpha \cdot \frac{\theta(\alpha\theta)^{\frac{\alpha}{1-\alpha}}t_e + (1-t_e)}{\left(1+\left((\alpha\theta)^{\frac{1}{1-\alpha}}-1\right)t_e\right)^\alpha} \qquad (17)

or equivalently:

z0(te)=lˉα1+(Λα1)te(1+(Λ1)te)αz_0(t_e) = \bar{l}^\alpha \cdot \frac{1+\left(\frac{\Lambda}{\alpha}-1\right)t_e}{(1+(\Lambda-1)t_e)^\alpha}

Derivation: Following the same approach as equation (5), we substitute le0(te)=Λte1+(Λ1)tel_e^0(t_e) = \frac{\Lambda t_e}{1+(\Lambda-1)t_e} into:

z0(te)=[θte1α(le0)α+(1te)1α(1le0)α]Alˉαz_0(t_e) = \left[\theta t_e^{1-\alpha}(l_e^0)^\alpha + (1-t_e)^{1-\alpha}(1-l_e^0)^\alpha\right] \cdot A\bar{l}^\alpha

Break into terms A=θte1α(le0)αA = \theta t_e^{1-\alpha}(l_e^0)^\alpha and B=(1te)1α(1le0)αB = (1-t_e)^{1-\alpha}(1-l_e^0)^\alpha.

Term A:

A=θte1α(Λte1+(Λ1)te)α=θteΛα(1+(Λ1)te)αA = \theta t_e^{1-\alpha}\left(\frac{\Lambda t_e}{1+(\Lambda-1)t_e}\right)^\alpha = \theta \cdot \frac{t_e \cdot \Lambda^\alpha}{(1+(\Lambda-1)t_e)^\alpha}

Mathematical Trick: Recall from equation (12) that:

θΛα=θ(αθ)α1α=Λα\theta \cdot \Lambda^\alpha = \theta \cdot (\alpha\theta)^{\frac{\alpha}{1-\alpha}} = \frac{\Lambda}{\alpha}

(Proof: θ(αθ)α1α=θ1+α1ααα1α=θ11ααα1α=(αθ)11αα1=Λα\theta \cdot (\alpha\theta)^{\frac{\alpha}{1-\alpha}} = \theta^{1+\frac{\alpha}{1-\alpha}} \cdot \alpha^{\frac{\alpha}{1-\alpha}} = \theta^{\frac{1}{1-\alpha}} \cdot \alpha^{\frac{\alpha}{1-\alpha}} = (\alpha\theta)^{\frac{1}{1-\alpha}} \cdot \alpha^{-1} = \frac{\Lambda}{\alpha})

Therefore:

A=1αΛte(1+(Λ1)te)αA = \frac{1}{\alpha} \cdot \frac{\Lambda t_e}{(1+(\Lambda-1)t_e)^\alpha}

Term B: As before, 1le0=1te1+(Λ1)te1-l_e^0 = \frac{1-t_e}{1+(\Lambda-1)t_e}, so:

B=1te(1+(Λ1)te)αB = \frac{1-t_e}{(1+(\Lambda-1)t_e)^\alpha}

Combining:

A+B=Λαte+(1te)(1+(Λ1)te)α=1+(Λα1)te(1+(Λ1)te)αA + B = \frac{\frac{\Lambda}{\alpha}t_e + (1-t_e)}{(1+(\Lambda-1)t_e)^\alpha} = \frac{1+(\frac{\Lambda}{\alpha}-1)t_e}{(1+(\Lambda-1)t_e)^\alpha}

Alternatively, using θΛα=Λ/α\theta \Lambda^\alpha = \Lambda/\alpha:

z0(te)=lˉαθΛαte+(1te)(1+(Λ1)te)αz_0(t_e) = \bar{l}^\alpha \cdot \frac{\theta \Lambda^\alpha t_e + (1-t_e)}{(1+(\Lambda-1)t_e)^\alpha}

Note: Unlike the first-best z1(te)=lˉα(1+(Λo1)te)1αz_1(t_e) = \bar{l}^\alpha(1+(\Lambda_o-1)t_e)^{1-\alpha} which is always concave, z0(te)z_0(t_e) can be either concave or convex depending on θ\theta relative to θH=1/α\theta_H = 1/\alpha.


Equation (18): Second-Best Threshold (Low-TFP Region)

When θ<θH=1/α\theta < \theta_H = 1/\alpha (so Λ<1\Lambda < 1), the objective z0(te)z_0(t_e) is convex. The second-best planner chooses full enclosure when:

z0(1)cz0(0)lˉ[cA(θ1)]1α=lˉs(18)z_0(1) - c \geq z_0(0) \Leftrightarrow \bar{l} \geq \left[\frac{c}{A(\theta-1)}\right]^{\frac{1}{\alpha}} = \bar{l}^s \qquad (18)

Derivation: With convex objective, compare corner solutions.

At te=0t_e = 0:

z0(0)=lˉα11=lˉαz_0(0) = \bar{l}^\alpha \cdot \frac{1}{1} = \bar{l}^\alpha

At te=1t_e = 1:

z0(1)=lˉα1+(Λα1)Λα=lˉαΛαΛα=lˉα1αΛα1z_0(1) = \bar{l}^\alpha \cdot \frac{1+(\frac{\Lambda}{\alpha}-1)}{\Lambda^\alpha} = \bar{l}^\alpha \cdot \frac{\frac{\Lambda}{\alpha}}{\Lambda^\alpha} = \bar{l}^\alpha \cdot \frac{1}{\alpha\Lambda^{\alpha-1}}

Actually, let’s compute more carefully. At te=1t_e=1:

z0(1)=lˉαΛ/αΛα=lˉα1αΛα1z_0(1) = \bar{l}^\alpha \cdot \frac{\Lambda/\alpha}{\Lambda^\alpha} = \bar{l}^\alpha \cdot \frac{1}{\alpha \Lambda^{\alpha-1}}

Hmm, let me reconsider. Actually for Cobb-Douglas when all land is enclosed:

z0(1)=A[θ11α1α+0]lˉα=Aθlˉαz_0(1) = A[\theta \cdot 1^{1-\alpha} \cdot 1^\alpha + 0] \cdot \bar{l}^\alpha = A\theta\bar{l}^\alpha

And at te=0t_e=0:

z0(0)=A[0+11α1α]lˉα=Alˉαz_0(0) = A[0 + 1^{1-\alpha} \cdot 1^\alpha] \cdot \bar{l}^\alpha = A\bar{l}^\alpha

For full enclosure to be preferred:

z0(1)cz0(0)z_0(1) - c \geq z_0(0)

AθlˉαcAlˉαA\theta\bar{l}^\alpha - c \geq A\bar{l}^\alpha

A(θ1)lˉαcA(\theta-1)\bar{l}^\alpha \geq c

lˉ[cA(θ1)]1α\bar{l} \geq \left[\frac{c}{A(\theta-1)}\right]^{\frac{1}{\alpha}}

This is the threshold for full enclosure in the low-TFP region where strategic complementarities create potential for multiple equilibria.


Equation (19): Second-Best No-Enclosure Threshold (High-TFP)

When θθH\theta \geq \theta_H (so Λ1\Lambda \geq 1), z0(te)z_0(t_e) is concave. The second-best planner begins enclosing when:

z0(0)clˉ[cA((αθ)11α(1+α)α)1(1α)]1α=lˉ0s(19)z_0'(0) \geq c \Leftrightarrow \bar{l} \geq \left[\frac{c}{A\left((\alpha\theta)^{\frac{1}{1-\alpha}}(1+\alpha)-\alpha\right)} \cdot \frac{1}{(1-\alpha)}\right]^{\frac{1}{\alpha}} = \bar{l}_0^s \qquad (19)

Derivation: We need to compute z0(te)z_0'(t_e) using the quotient rule on:

z0(te)=lˉα1+(Λα1)te(1+(Λ1)te)αz_0(t_e) = \bar{l}^\alpha \cdot \frac{1+(\frac{\Lambda}{\alpha}-1)t_e}{(1+(\Lambda-1)t_e)^\alpha}

Let u=1+(Λα1)teu = 1+(\frac{\Lambda}{\alpha}-1)t_e and v=(1+(Λ1)te)αv = (1+(\Lambda-1)t_e)^\alpha.

Then:

dudte=Λα1\frac{d u}{dt_e} = \frac{\Lambda}{\alpha}-1
dvdte=α(1+(Λ1)te)α1(Λ1)\frac{dv}{dt_e} = \alpha(1+(\Lambda-1)t_e)^{\alpha-1} \cdot (\Lambda-1)

By quotient rule:

z0(te)=lˉαvuuvv2z_0'(t_e) = \bar{l}^\alpha \cdot \frac{v \cdot u' - u \cdot v'}{v^2}
=lˉα(1+(Λ1)te)α(Λα1)[1+(Λα1)te]α(1+(Λ1)te)α1(Λ1)(1+(Λ1)te)2α= \bar{l}^\alpha \cdot \frac{(1+(\Lambda-1)t_e)^\alpha \cdot (\frac{\Lambda}{\alpha}-1) - [1+(\frac{\Lambda}{\alpha}-1)t_e] \cdot \alpha(1+(\Lambda-1)t_e)^{\alpha-1}(\Lambda-1)}{(1+(\Lambda-1)t_e)^{2\alpha}}

Factor out (1+(Λ1)te)α1(1+(\Lambda-1)t_e)^{\alpha-1}:

=lˉα(1+(Λ1)te)(Λα1)[1+(Λα1)te]α(Λ1)(1+(Λ1)te)α+1= \bar{l}^\alpha \cdot \frac{(1+(\Lambda-1)t_e)(\frac{\Lambda}{\alpha}-1) - [1+(\frac{\Lambda}{\alpha}-1)t_e] \cdot \alpha(\Lambda-1)}{(1+(\Lambda-1)t_e)^{\alpha+1}}

At te=0t_e = 0:

z0(0)=lˉαΛα1α(Λ1)1z_0'(0) = \bar{l}^\alpha \cdot \frac{\frac{\Lambda}{\alpha}-1 - \alpha(\Lambda-1)}{1}
=lˉα[Λα1αΛ+α]= \bar{l}^\alpha \cdot \left[\frac{\Lambda}{\alpha}-1 - \alpha\Lambda + \alpha\right]
=lˉα[ΛααΛ+α1]= \bar{l}^\alpha \cdot \left[\frac{\Lambda}{\alpha} - \alpha\Lambda + \alpha - 1\right]
=lˉα[Λ(1αα)+(α1)]= \bar{l}^\alpha \cdot \left[\Lambda\left(\frac{1}{\alpha} - \alpha\right) + (\alpha-1)\right]
=lˉα[Λ1α2α(1α)]= \bar{l}^\alpha \cdot \left[\Lambda \cdot \frac{1-\alpha^2}{\alpha} - (1-\alpha)\right]
=lˉα(1α)[Λ1+αα1]= \bar{l}^\alpha(1-\alpha) \cdot \left[\Lambda \cdot \frac{1+\alpha}{\alpha} - 1\right]
=lˉα(1α)[Λ(1+α)αα]= \bar{l}^\alpha(1-\alpha) \cdot \left[\frac{\Lambda(1+\alpha) - \alpha}{\alpha}\right]

Set z0(0)=cz_0'(0) = c:

lˉα(1α)Λ(1+α)αα=c\bar{l}^\alpha(1-\alpha) \cdot \frac{\Lambda(1+\alpha) - \alpha}{\alpha} = c
lˉα=cα(1α)[Λ(1+α)α]\bar{l}^\alpha = \frac{c\alpha}{(1-\alpha)[\Lambda(1+\alpha)-\alpha]}
lˉ=[cαA(1α)[(αθ)11α(1+α)α]]1α\bar{l} = \left[\frac{c\alpha}{A(1-\alpha)[(\alpha\theta)^{\frac{1}{1-\alpha}}(1+\alpha)-\alpha]}\right]^{\frac{1}{\alpha}}

Rearranging:

lˉ0s=[cA((αθ)11α(1+α)α)1(1α)]1α\bar{l}_0^s = \left[\frac{c}{A\left((\alpha\theta)^{\frac{1}{1-\alpha}}(1+\alpha)-\alpha\right)} \cdot \frac{1}{(1-\alpha)}\right]^{\frac{1}{\alpha}}

Equation (20): Second-Best Full-Enclosure Threshold (High-TFP)

The second-best planner chooses full enclosure when:

z0(1)clˉ[cθA(1α)]1α=lˉ1s(20)z_0'(1) \geq c \Leftrightarrow \bar{l} \geq \left[\frac{c}{\theta A(1-\alpha)}\right]^{\frac{1}{\alpha}} = \bar{l}_1^s \qquad (20)

Derivation: At te=1t_e = 1, we evaluate the derivative. From the general formula:

z0(te)=lˉα(1+(Λ1)te)(Λα1)[1+(Λα1)te]α(Λ1)(1+(Λ1)te)α+1z_0'(t_e) = \bar{l}^\alpha \cdot \frac{(1+(\Lambda-1)t_e)(\frac{\Lambda}{\alpha}-1) - [1+(\frac{\Lambda}{\alpha}-1)t_e] \cdot \alpha(\Lambda-1)}{(1+(\Lambda-1)t_e)^{\alpha+1}}

At te=1t_e = 1:

z0(1)=lˉαΛ(Λα1)Λαα(Λ1)Λα+1z_0'(1) = \bar{l}^\alpha \cdot \frac{\Lambda(\frac{\Lambda}{\alpha}-1) - \frac{\Lambda}{\alpha} \cdot \alpha(\Lambda-1)}{\Lambda^{\alpha+1}}
=lˉαΛ2αΛΛ(Λ1)Λα+1= \bar{l}^\alpha \cdot \frac{\frac{\Lambda^2}{\alpha}-\Lambda - \Lambda(\Lambda-1)}{\Lambda^{\alpha+1}}
=lˉαΛ2αΛΛ2+ΛΛα+1= \bar{l}^\alpha \cdot \frac{\frac{\Lambda^2}{\alpha}-\Lambda - \Lambda^2 + \Lambda}{\Lambda^{\alpha+1}}
=lˉαΛ2αΛ2Λα+1= \bar{l}^\alpha \cdot \frac{\frac{\Lambda^2}{\alpha} - \Lambda^2}{\Lambda^{\alpha+1}}
=lˉαΛ2(1α1)Λα+1= \bar{l}^\alpha \cdot \frac{\Lambda^2({\frac{1}{\alpha} - 1})}{\Lambda^{\alpha+1}}
=lˉαΛ21ααΛα+1= \bar{l}^\alpha \cdot \frac{\Lambda^2 \cdot \frac{1-\alpha}{\alpha}}{\Lambda^{\alpha+1}}
=lˉα(1α)αΛα1= \bar{l}^\alpha \cdot \frac{(1-\alpha)}{\alpha\Lambda^{\alpha-1}}

But recall Λ=(αθ)11α\Lambda = (\alpha\theta)^{\frac{1}{1-\alpha}}, so Λα1=(αθ)α11α=(αθ)1\Lambda^{\alpha-1} = (\alpha\theta)^{\frac{\alpha-1}{1-\alpha}} = (\alpha\theta)^{-1}.

z0(1)=lˉα(1α)ααθ=lˉαθ(1α)z_0'(1) = \bar{l}^\alpha \cdot \frac{(1-\alpha)}{\alpha} \cdot \alpha\theta = \bar{l}^\alpha \theta(1-\alpha)

Set z0(1)=cz_0'(1) = c:

lˉαθ(1α)=c\bar{l}^\alpha \theta(1-\alpha) = c
lˉ=[cθA(1α)]1α\bar{l} = \left[\frac{c}{\theta A(1-\alpha)}\right]^{\frac{1}{\alpha}}

Important Note: This equals lˉ1d\bar{l}_1^d from equation (14)! The second-best and private thresholds for full enclosure coincide.

First-best, second-best and private enclosure thresholds compared.

Figure 3:First-best, second-best and private enclosure thresholds compared.


4.2 Sources of Inefficiency

Equation (21): Decomposition of Social Marginal Benefit

The derivative of the second-best objective can be decomposed as:

z0(te)c=θFTeAlˉαprivate returnFTcAlˉαdisplaced rents+(θFLeFLc)Alˉαdle0dtelabor reallocation effectc(21)z_0'(t_e) - c = \underbrace{\theta F_T^e A\bar{l}^\alpha}_{\text{private return}} - \underbrace{F_T^c A\bar{l}^\alpha}_{\text{displaced rents}} + \underbrace{(\theta F_L^e - F_L^c)A\bar{l}^\alpha \cdot \frac{dl_e^0}{dt_e}}_{\text{labor reallocation effect}} - c \qquad (21)

Derivation: Apply the chain rule to z0(te)=[θF(te,le0(te))+F(1te,1le0(te))]Alˉαz_0(t_e) = [\theta F(t_e, l_e^0(t_e)) + F(1-t_e, 1-l_e^0(t_e))] \cdot A\bar{l}^\alpha:

z0(te)=[θFTe+θFLedle0dte+FTc(1)+FLc(dle0dte)]Alˉαz_0'(t_e) = \left[\theta F_T^e + \theta F_L^e \cdot \frac{dl_e^0}{dt_e} + F_T^c \cdot (-1) + F_L^c \cdot \left(-\frac{dl_e^0}{dt_e}\right)\right] \cdot A\bar{l}^\alpha

where we use the notation:

Rearranging:

z0(te)=[(θFTeFTc)+(θFLeFLc)dle0dte]Alˉαz_0'(t_e) = \left[(\theta F_T^e - F_T^c) + (\theta F_L^e - F_L^c)\frac{dl_e^0}{dt_e}\right] \cdot A\bar{l}^\alpha

Interpretation:

  1. Private Return (θFTeAlˉα\theta F_T^e A\bar{l}^\alpha): The rental income captured by the encloser. This is what drives private enclosure decisions.

  2. Displaced Rents (FTcAlˉα-F_T^c A\bar{l}^\alpha): The marginal product of land in the commons that is lost when a unit of land is enclosed. Private enclosers do not internalize this loss, creating a negative externality that leads to over-enclosure.

  3. Labor Reallocation Effect ((θFLeFLc)Alˉαdle0dte(\theta F_L^e - F_L^c)A\bar{l}^\alpha \cdot \frac{dl_e^0}{dt_e}): When land is enclosed, labor reallocates from the commons (where it earns average product) to the enclosed sector (where it earns marginal product). This reduces the efficiency cost of labor misallocation. Private enclosers don’t capture this benefit, creating a positive externality that leads to under-enclosure.

Supporting Calculations:

For Cobb-Douglas, we can compute explicit expressions:

Marginal Product of Land (Enclosed):

FTe=(1α)(le0(te)te)α=(1α)(Λ1+(Λ1)te)αF_T^e = (1-\alpha) \cdot \left(\frac{l_e^0(t_e)}{t_e}\right)^\alpha = (1-\alpha)\left(\frac{\Lambda}{1+(\Lambda-1)t_e}\right)^\alpha

Marginal Product of Land (Commons):

FTc=(1α)(1le0(te)1te)α=(1α)(11+(Λ1)te)αF_T^c = (1-\alpha) \cdot \left(\frac{1-l_e^0(t_e)}{1-t_e}\right)^\alpha = (1-\alpha)\left(\frac{1}{1+(\Lambda-1)t_e}\right)^\alpha

Marginal Product of Labor (Enclosed):

FLe=αθ(1+(Λ1)te)1αF_L^e = \alpha\theta(1+(\Lambda-1)t_e)^{1-\alpha}

Marginal Product of Labor (Commons):

FLc=α(1+(Λ1)te)1αF_L^c = \alpha(1+(\Lambda-1)t_e)^{1-\alpha}

Derivative of Labor Allocation:

dle0dte=Λ(1+(Λ1)te)2\frac{dl_e^0}{dt_e} = \frac{\Lambda}{(1+(\Lambda-1)t_e)^2}

These expressions show precisely how the three effects vary with tet_e and parameters (θ,α)(\theta, \alpha).

Key Result: The private enclosure decision (r(te)=cr(t_e) = c) ignores both the displaced rents term and the labor reallocation term. Depending on which effect dominates, private enclosure can be excessive or insufficient relative to the second-best.

MPL, APL and the labor misallocation wedge.

Figure 4:MPL, APL and the labor misallocation wedge.


[End of Section 4]


Section 5: The Extended Model

The baseline model assumes complete open access to unenclosed land (μ=0\mu=0) and no compensation for displacement (τ=0\tau=0). We now introduce institutional parameters to capture variations in governance quality and power relations.

5.1 The Regulated Commons

Equation (22): Labor Equilibrium with Governance

We generalize the labor market equilibrium to allow for partial regulation of the commons. Define μ[0,1]\mu \in [0,1] as a governance parameter where:

The labor equilibrium condition becomes:

wewc=(1μ)rcTcLc(22)w_e - w_c = (1-\mu) \cdot r_c \cdot \frac{T_c}{L_c} \qquad (22)

Derivation: Under imperfect governance of the commons, a worker who moves to the enclosed sector gives up not only their labor income but also a fraction (1μ)(1-\mu) of the possession rents they were capturing in the commons.

The wage in the enclosed sector is the marginal product of labor:

we=θαA(tele)1αlˉαw_e = \theta \alpha A\left(\frac{t_e}{l_e}\right)^{1-\alpha}\bar{l}^\alpha

The effective return in the commons is:

wc=αA(1te1le)1αlˉα+(1μ)rcTcLcw_c = \alpha A\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha}\bar{l}^\alpha + (1-\mu) \cdot r_c \cdot \frac{T_c}{L_c}

where rc=(1α)A(1le1te)αlˉαr_c = (1-\alpha)A\left(\frac{1-l_e}{1-t_e}\right)^\alpha\bar{l}^\alpha is the marginal product of land in the commons.

Setting we=wcw_e = w_c gives equation (22).

Interpretation:


Equation (23): Modified Labor Reaction Function

With governance parameter μ\mu, the labor allocation function becomes:

leμ(te)=Λμte1+(Λμ1)te(23)l_e^\mu(t_e) = \frac{\Lambda_\mu t_e}{1+(\Lambda_\mu-1)t_e} \qquad (23)

where

Λμ=(αθ1μ(1α))11α\Lambda_\mu = \left(\frac{\alpha\theta}{1-\mu(1-\alpha)}\right)^{\frac{1}{1-\alpha}}

Derivation: From the equilibrium condition (22), we can show:

θα(tele)1α=[1μ(1α)](1te1le)1α\theta \alpha \left(\frac{t_e}{l_e}\right)^{1-\alpha} = [1-\mu(1-\alpha)]\left(\frac{1-t_e}{1-l_e}\right)^{1-\alpha}

Raise to power 11α\frac{1}{1-\alpha}:

(αθ1μ(1α))11αtele=1te1le\left(\frac{\alpha\theta}{1-\mu(1-\alpha)}\right)^{\frac{1}{1-\alpha}} \cdot \frac{t_e}{l_e} = \frac{1-t_e}{1-l_e}

Defining Λμ\Lambda_\mu as above and following the same algebraic steps as equations (4) and (10), we obtain equation (23).

Key Properties:


Equation (24): Modified High-TFP Threshold

The threshold separating strategic complements from strategic substitutes shifts with μ\mu:

θHμ=1αμ1αα(24)\theta_H^\mu = \frac{1}{\alpha} - \mu \cdot \frac{1-\alpha}{\alpha} \qquad (24)

Derivation: The critical threshold occurs when Λμ=1\Lambda_\mu = 1:

(αθ1μ(1α))11α=1\left(\frac{\alpha\theta}{1-\mu(1-\alpha)}\right)^{\frac{1}{1-\alpha}} = 1
αθ1μ(1α)=1\frac{\alpha\theta}{1-\mu(1-\alpha)} = 1
αθ=1μ(1α)\alpha\theta = 1-\mu(1-\alpha)
θ=1μ(1α)α=1αμ1αα\theta = \frac{1-\mu(1-\alpha)}{\alpha} = \frac{1}{\alpha} - \mu \cdot \frac{1-\alpha}{\alpha}

Implications:

Labor allocation curves l_e^\mu(t_e) for different values of \mu.

Figure 5:Labor allocation curves leμ(te)l_e^\mu(t_e) for different values of μ\mu.


5.2 Power and Compensation

Equation (25): Profitability with Compensation

Now introduce parameter τ[0,1]\tau \in [0,1] representing the fraction of displaced rents that enclosers must compensate. Private enclosure is profitable when:

θFTeAlˉατFTcAlˉαc0(25)\theta F_T^e A\bar{l}^\alpha - \tau \cdot F_T^c A\bar{l}^\alpha - c \geq 0 \qquad (25)

Derivation:

The net return is:

πe=θFTeAlˉατFTcAlˉαc\pi_e = \theta F_T^e A\bar{l}^\alpha - \tau F_T^c A\bar{l}^\alpha - c

Enclosure occurs when πe0\pi_e \geq 0, giving equation (25).

Interpretation:


5.3 The Extended Wedge: A Unified Framework

Equation (26): Combined Governance and Compensation Effects

The social return to enclosure with both institutional parameters is:

z0(te)=θFTeAlˉα(1τ)FTcAlˉα+(1μ)FTcAlˉαTcLcdleμdtec(26)z_0'(t_e) = \theta F_T^e A\bar{l}^\alpha - (1-\tau)F_T^c A\bar{l}^\alpha + (1-\mu)F_T^c A\bar{l}^\alpha \frac{T_c}{L_c} \cdot \frac{dl_e^\mu}{dt_e} - c \qquad (26)

Derivation: This extends equation (21) by:

  1. Scaling the displaced rents term by (1τ)(1-\tau) - compensation internalizes fraction τ\tau

  2. Scaling the labor reallocation term by (1μ)(1-\mu) - governance reduces misallocation

The labor reallocation effect now uses leμ(te)l_e^\mu(t_e) instead of le0(te)l_e^0(t_e), and the magnitude of the effect is proportional to (1μ)(1-\mu) since better governance reduces the initial misallocation.

Key Result: The wedge between private and social returns closes when:

With both parameters at 1, private incentives align with social optimum. However, improving only one dimension while holding the other fixed can worsen outcomes (second-best problem).


Equation (27): General Enclosure Decision

Private enclosure with both institutional parameters occurs when:

rμe(te)τrμc(te)c0(27)r_\mu^e(t_e) - \tau \cdot r_\mu^c(t_e) - c \geq 0 \qquad (27)

where:

rμe(te)=θ(1α)Alˉα(Λμ1+(Λμ1)te)αr_\mu^e(t_e) = \theta(1-\alpha)A\bar{l}^\alpha \left(\frac{\Lambda_\mu}{1+(\Lambda_\mu-1)t_e}\right)^\alpha
rμc(te)=(1α)Alˉα(11+(Λμ1)te)αr_\mu^c(t_e) = (1-\alpha)A\bar{l}^\alpha \left(\frac{1}{1+(\Lambda_\mu-1)t_e}\right)^\alpha

This generalizes equation (12) to allow for both governance quality (μ\mu) and compensation requirements (τ\tau).

Effects of varying \mu and \tau on equilibrium outcomes.

Figure 6:Effects of varying μ\mu and τ\tau on equilibrium outcomes.


Equation (27a): Global Games Threshold under Governance and Compensation

Equations (13)–(14) generalize to the extended model by substituting (27) for (12), and so does the selection criterion of equation (15). The multiplicity region does not disappear when μ\mu or τ\tau is positive — it is θ<θHμ\theta < \theta_H^\mu, which is non-empty for every μ[0,1]\mu \in [0,1] — so a risk-dominance threshold continues to exist there and can be written down.

The two rents in (27) share the same dependence on tet_e, so they combine before integrating:

rμe(te)τrμc(te)=(1α)Alˉα(θΛματ)(1+(Λμ1)te)αr_\mu^e(t_e) - \tau\,r_\mu^c(t_e) = (1-\alpha)A\bar{l}^{\alpha}\left(\theta\Lambda_\mu^{\alpha}-\tau\right) \left(1+(\Lambda_\mu-1)t_e\right)^{-\alpha}

Applying the same substitution as in (15) gives

lˉggd(μ,τ)=[(c/A)(Λμ1)(θΛματ)(Λμ1α1)]1α(27a)\bar{l}_{gg}^d(\mu,\tau) = \left[\frac{(c/A)\left(\Lambda_\mu-1\right)} {\left(\theta\Lambda_\mu^{\alpha}-\tau\right)\left(\Lambda_\mu^{1-\alpha}-1\right)} \right]^{\frac{1}{\alpha}} \qquad (27a)

Properties:

Comparative statics. The two institutional parameters move the threshold in opposite directions. Compensation raises it: τ\tau enters only through (θΛματ)(\theta\Lambda_\mu^\alpha - \tau), so a larger τ\tau shrinks the expected return and a higher density is needed to trigger the cascade. Governance lowers it. Raising μ\mu reduces AμA_\mu, which raises Λμ\Lambda_\mu and hence the encloser’s return θΛμα\theta\Lambda_\mu^{\alpha} — a regulated commons pays labor its marginal rather than its average product, so the outside wage an encloser must match is lower. At α=2/3\alpha=2/3, θ=0.9\theta=0.9, τ=0\tau=0:

μ\muAμA_\muΛμ\Lambda_\muθΛμα\theta\Lambda_\mu^{\alpha}lnlˉggd\ln \bar{l}_{gg}^d
0.01.0000.2160.3242.700
0.30.9000.2960.4002.495
0.60.8000.4220.5062.279
1.00.6670.7290.7291.970

Better commons governance therefore makes the enclosure race easier to trigger, at the same time as it shrinks the region in which a race is possible at all, since θHμ\theta_H^\mu falls from 1/α1/\alpha to 1 over the same range. The two effects work against each other, and which dominates is a quantitative question.

Verification: (27a) was checked against symbolic integration, against numerical quadrature of the payoff, and by reduction to the two one-sided forms already implemented in the code — equation (15) extended in τ\tau at μ=0\mu=0, and the μ\mu-extended form at τ=0\tau=0.


Equation (27b): Where the Selection Threshold Ceases to Exist

The condition θΛμα>τ\theta\Lambda_\mu^{\alpha} > \tau in (27a) has a closed-form boundary. Setting the two equal and using Λμ1α=αθ/Aμ\Lambda_\mu^{1-\alpha} = \alpha\theta/A_\mu:

θ(αθAμ)α1α=τθτ(μ,τ)=τ1α(Aμα)α(27b)\theta\left(\frac{\alpha\theta}{A_\mu}\right)^{\frac{\alpha}{1-\alpha}} = \tau \qquad\Longrightarrow\qquad \theta_\tau(\mu,\tau) = \tau^{1-\alpha}\left(\frac{A_\mu}{\alpha}\right)^{\alpha} \qquad (27b)

At τ=0\tau=0 this is 0, imposing nothing. At μ=0,τ=1\mu=0,\tau=1 it is αα\alpha^{-\alpha} (1.310\approx 1.310 at α=2/3\alpha=2/3), the asymptote of the τ=1\tau=1 locus.

Why this is a different kind of boundary. Both rents in (27) carry the same factor lˉα\bar l^{\alpha}, so it factors out of the comparison entirely:

rμeτrμc=(1α)Alˉα(θΛματ)no lˉ(1+(Λμ1)te)αr_\mu^e - \tau r_\mu^c = (1-\alpha)A\bar{l}^{\alpha} \underbrace{\left(\theta\Lambda_\mu^{\alpha}-\tau\right)}_{\text{no } \bar l} \left(1+(\Lambda_\mu-1)t_e\right)^{-\alpha}

Population density scales both the encloser’s gross return and the compensation owed, so it cannot change the sign of their difference. Below θτ\theta_\tau the expected net return is negative at every density: the threshold does not move upward out of reach, it ceases to exist.

This distinguishes the two obstacles to enclosure in the model:

how it enterscan density overcome it?
Enclosure cost cca level charge per unit landYes. Rents scale with lˉα\bar l^{\alpha} while cc does not, so some density always suffices. This is why every locus is downward-sloping and finite.
Compensation τ\taua proportional claim on displaced rentsNo. It scales with the thing it taxes, so the comparison is density-free. Below θτ\theta_\tau no density suffices.

The distinction matters for the Boserupian reading of the model. Rising population density is the mechanism that drives an economy through every other threshold in the paper — lˉ01\bar l_0^1, lˉ0d\bar l_0^d, lˉggd\bar l_{gg}^d. Compensation is the one institution it cannot push through. Cost-based protections for customary users — titling fees, registration requirements, administrative friction — are eroded by population growth, because they are levels. A compensation requirement is not, because it is a share.

Closure at the corner. Since θHμ=Aμ/α\theta_H^\mu = A_\mu/\alpha and θτ=τ1α(Aμ/α)α\theta_\tau = \tau^{1-\alpha}(A_\mu/\alpha)^{\alpha}, the interval (θτ,θHμ)(\theta_\tau, \theta_H^\mu) is non-empty whenever τ<1\tau < 1 or μ<1\mu < 1, and empty exactly at μ=τ=1\mu=\tau=1, where both equal 1. So the coordination problem vanishes at precisely the corner where the wedge closes: complete governance and complete compensation not only align the decentralized loci with the planner’s (§5.3), they eliminate the multiplicity that made equilibrium selection necessary in the first place. Neither parameter achieves this alone — at μ<1\mu<1 a multiplicity region survives even at τ=1\tau=1, since (Aμ/α)α<Aμ/α(A_\mu/\alpha)^{\alpha} < A_\mu/\alpha whenever Aμ/α>1A_\mu/\alpha > 1.


[End of Section 5]


Section 6: Applications and Extensions

6.1 Labor Release and Wages

Equation (28): Total Labor Income (Access Fees Redistributed)

When access fees collected in the commons are redistributed to labor, total labor income is:

YL=AF(Tˉ,Lˉ)1+(αθΛμ1)te(1+(Λμ1)te)α(28)Y_L = AF(\bar{T}, \bar{L}) \cdot \frac{1+(\alpha\theta\Lambda_\mu-1)t_e}{(1+(\Lambda_\mu-1)t_e)^\alpha} \qquad (28)

Derivation: Labor earns:

Total labor income:

YL=αθAF(Te,Le)+AF(Tc,Lc)Y_L = \alpha\theta AF(T_e, L_e) + AF(T_c, L_c)

Factoring out AF(Tˉ,Lˉ)AF(\bar{T}, \bar{L}) and expressing in shares:

YL=AF(Tˉ,Lˉ)[αθF(te,leμ)+F(1te,1leμ)]Y_L = AF(\bar{T}, \bar{L})[\alpha\theta F(t_e, l_e^\mu) + F(1-t_e, 1-l_e^\mu)]

Substituting leμ(te)l_e^\mu(t_e) and simplifying (similar to derivations in equations 5 and 17) yields equation (28).

Result: Labor benefits from enclosure when θ>θHμ\theta > \theta_H^\mu, as the productivity gains outweigh the loss of commons access.


Equation (29): Total Labor Income (Access Fees Captured by Elites)

If elites capture the fraction (1μ)(1-\mu) of possession rents:

YL=(1μ(1α))AF(Tˉ,Lˉ)(1+(Λμ1)te)1α(29)Y_L = (1-\mu(1-\alpha))AF(\bar{T}, \bar{L})(1+(\Lambda_\mu-1)t_e)^{1-\alpha} \qquad (29)

Derivation: Labor now earns only:

Total:

YL=α[θF(Te,Le)+F(Tc,Lc)]+μ(1α)F(Tc,Lc)Y_L = \alpha[\theta F(T_e, L_e) + F(T_c, L_c)] + \mu(1-\alpha)F(T_c, L_c)

After substitution and simplification, this leads to equation (29).

Result: With elite capture, labor’s share of income is reduced by factor (1μ(1α))(1-\mu(1-\alpha)), highlighting distributional consequences of weak governance.


6.2 Power Shifts and Contested Claims

(No new numbered equations - qualitative discussion)

The framework can be applied to analyze:


6.3 Encompassing Interests and Frontier Colonization

Equation (30): Monopolistic Encloser’s Profit

A monopolistic encloser (e.g., colonial authority, land syndicate) maximizes total profit:

π(te)=r(te)tecte(30)\pi(t_e) = r(t_e) \cdot t_e - c \cdot t_e \qquad (30)

Derivation: Unlike competitive enclosers who take r(te)r(t_e) as given, a monopolist internalizes the effect of their enclosure decisions on the rental rate. Total profit is rental income minus enclosure costs.


Equations (31-34): Monopoly Thresholds

Low-TFP Region: Monopolist chooses full enclosure when:

π(1)>0lˉ[cθA(1α)]1α=lˉm(31)\pi(1) > 0 \Leftrightarrow \bar{l} \geq \left[\frac{c}{\theta A(1-\alpha)}\right]^{\frac{1}{\alpha}} = \bar{l}^m \qquad (31)

This equals lˉ1d\bar{l}_1^d, but the monopolist jumps directly to full enclosure (Wakefield’s “sufficient price”).

High-TFP Region: Monopolist begins enclosing when:

π(0)0lˉlˉ0m(32)\pi'(0) \geq 0 \Leftrightarrow \bar{l} \geq \bar{l}_0^m \qquad (32)

And fully encloses when:

π(1)0lˉlˉ1m(33)\pi'(1) \geq 0 \Leftrightarrow \bar{l} \geq \bar{l}_1^m \qquad (33)

Derivation: From π(te)=r(te)+r(te)tec\pi'(t_e) = r(t_e) + r'(t_e)t_e - c, evaluate at boundaries. The monopolist restricts enclosure below competitive levels when r(te)<0r'(t_e) < 0 (high-TFP), as they internalize the rent-reducing effect of enclosure.

Monopolist’s enclosure decisions vs. competitive outcomes.

Figure 7:Monopolist’s enclosure decisions vs. competitive outcomes.


6.4 Structural Transformation and Manufacturing

Equation (35): Labor Market with Manufacturing

Extend to three sectors (enclosed agriculture, commons agriculture, manufacturing):

le+lc+lm=1(35)l_e + l_c + l_m = 1 \qquad (35)

where lml_m is labor share in manufacturing.


Equation (36): Modified Labor Allocation

The agricultural labor allocation becomes:

leμ(te)=Λμte1+(Λμ1)te(1lm)(36)l_e^\mu(t_e) = \frac{\Lambda_\mu t_e}{1+(\Lambda_\mu-1)t_e} \cdot (1-l_m) \qquad (36)

Derivation: The intra-agricultural condition is unchanged — equation (22) equalizes returns between enclosed land and the commons whatever else the economy contains — so the only modification is that the agricultural labor force is (1lm)(1-l_m) rather than 1. Following the steps of (23) with (1lm)(1-l_m) in place of 1 gives (36). The same expression with Λo\Lambda_o in place of Λμ\Lambda_\mu is the planner’s allocation, since μ=1\mu=1 gives Λ1=Λo\Lambda_1=\Lambda_o.

Everything below is stated in intensive form with tˉ=Tˉ/Lˉ\bar t = \bar T/\bar L and kˉ=Kˉ/Lˉ\bar k = \bar K/\bar L; factor-price levels carry the same density scaling as Section 3.


Equation (37): The Governance Wedge AμA_\mu

Labor in the commons takes home the fraction

Aμ=1μ(1α),A0=1,A1=α(37)A_\mu = 1 - \mu(1-\alpha), \qquad A_0 = 1, \quad A_1 = \alpha \qquad (37)

of the commons average product.

Derivation: From the Euler decomposition (8), APLc=MPLc+MPTc(Tc/Lc)AP_L^c = MP_L^c + MP_T^c \cdot (T_c/L_c), with MPLc=αAPLcMP_L^c = \alpha AP_L^c and hence MPTc(Tc/Lc)=(1α)APLcMP_T^c(T_c/L_c) = (1-\alpha)AP_L^c. Equation (22) says a worker leaving the commons forfeits the fraction μ\mu of those possession rents, retaining (1μ)(1-\mu). Total commons income per worker is therefore

wc=αAPLc+(1μ)(1α)APLc=[1μ(1α)]APLcw_c = \alpha AP_L^c + (1-\mu)(1-\alpha)AP_L^c = [1-\mu(1-\alpha)]\,AP_L^c

μ=0\mu=0 recovers open access, where labor captures the whole average product; μ=1\mu=1 gives the marginal product, which is the planner’s valuation.

AμA_\mu is stated separately from Λμ\Lambda_\mu because the two are not substitutes: Λμ\Lambda_\mu governs the slope of the labor allocation, AμA_\mu the level of what labor earns, and they enter subsequent expressions independently. The distinction is invisible in the two-sector model, where the level cannot affect an allocation that is agricultural regardless.


Equation (38): The Manufacturing Margin

Labor moves between sectors until pMPLm=θMPLe=wcp \cdot MP_L^m = \theta \cdot MP_L^e = w_c. Substituting (36) into each side:

pβkˉ1βCmlm(1β)  =  Aμtˉ1α(1+(Λμ1)te)1αCa(1lm)(1α)(38)\underbrace{p\beta\bar k^{1-\beta}}_{C_m} \cdot l_m^{-(1-\beta)} \;=\; \underbrace{A_\mu\,\bar t^{1-\alpha}\left(1+(\Lambda_\mu-1)t_e\right)^{1-\alpha}}_{C_a} \cdot (1-l_m)^{-(1-\alpha)} \qquad (38)

Derivation: From (36), 1lmleμ=(1lm)(1te)/[1+(Λμ1)te]1-l_m-l_e^\mu = (1-l_m)(1-t_e)/[1+(\Lambda_\mu-1)t_e], so

APLc=tˉ1α(1te1lmleμ)1α=tˉ1α(1+(Λμ1)te1lm)1αAP_L^c = \bar t^{1-\alpha}\left(\frac{1-t_e}{1-l_m-l_e^\mu}\right)^{1-\alpha} = \bar t^{1-\alpha}\left(\frac{1+(\Lambda_\mu-1)t_e}{1-l_m}\right)^{1-\alpha}

and wc=AμAPLcw_c = A_\mu \cdot AP_L^c by (37). Equivalently, working from the enclosed side, θMPLe=αθtˉ1α(te/leμ)1α=αθΛμ(1α)tˉ1α(1+(Λμ1)te)1α(1lm)(1α)\theta MP_L^e = \alpha\theta\,\bar t^{1-\alpha}(t_e/l_e^\mu)^{1-\alpha} = \alpha\theta\Lambda_\mu^{-(1-\alpha)}\bar t^{1-\alpha}(1+(\Lambda_\mu-1)t_e)^{1-\alpha}(1-l_m)^{-(1-\alpha)}, and αθΛμ(1α)=Aμ\alpha\theta\Lambda_\mu^{-(1-\alpha)} = A_\mu by the definition of Λμ\Lambda_\mu in (23). The two routes agree, as they must.

Note that at μ=0\mu=0 the prefactor equals exactly 1, so the agricultural side can be written compactly as tˉ1α(te/le0)1α\bar t^{1-\alpha}(t_e/l_e^0)^{1-\alpha}. That shorthand does not survive to μ>0\mu>0, where the prefactor is AμA_\mu and not 1.

Two properties pin the level and serve as checks:


Equation (39): Equilibrium Manufacturing Share

Rearranging (38):

lm1β(1lm)1α=CmCa(39)\frac{l_m^{1-\beta}}{(1-l_m)^{1-\alpha}} = \frac{C_m}{C_a} \qquad (39)

Existence and uniqueness. The left side is continuous and strictly increasing on (0,1)(0,1), from 0 to \infty. Hence (39) has exactly one solution for any Cm/Ca>0C_m/C_a > 0: the equilibrium exists and is unique for all admissible parameters, and a bracketed root-finder on (0,1)(0,1) is guaranteed to converge.

Closed form when β=α\beta=\alpha. The exponents coincide and (39) becomes (lm1lm)1α=CmCa\left(\frac{l_m}{1-l_m}\right)^{1-\alpha} = \frac{C_m}{C_a}, so

lm=R1+R,R=(CmCa)11αl_m = \frac{R}{1+R}, \qquad R = \left(\frac{C_m}{C_a}\right)^{\frac{1}{1-\alpha}}

For βα\beta\neq\alpha equation (39) is transcendental and has no elementary solution.

Comparative static in tet_e. Ca/te\partial C_a/\partial t_e has the sign of (Λμ1)(\Lambda_\mu-1). Because the left side of (39) is increasing in lml_m, the manufacturing share rises exactly when CaC_a falls, so

sign(lmte)=sign(1Λμ)\operatorname{sign}\left(\frac{\partial l_m}{\partial t_e}\right) = \operatorname{sign}(1-\Lambda_\mu)

— the opposite sign, an inversion easily lost. By (24), Λμ=1\Lambda_\mu=1 exactly at θHμ\theta_H^\mu, so enclosure accelerates structural transformation below that threshold, retards it above, and moves no labor at all at it. The knife-edge is exact. Equation (41) tabulates the consequences; note that θHμ\theta_H^\mu is the same threshold that separates strategic complements from substitutes in (24), a coincidence taken up there.


Equation (40): The Planner’s Enclosure Margin

Equations (36)–(39) condition on tet_e. Restoring the planner’s choice of tet_e, and applying the envelope theorem — at the planner’s allocation marginal products are already equal, so reallocating labor has no first-order effect and only the land-rent differential survives:

dYdte=(1α)tˉ1α(Λo1)(1lm(te)1+(Λo1)te)α(40)\frac{dY}{dt_e} = (1-\alpha)\,\bar t^{1-\alpha}(\Lambda_o-1)\left(\frac{1-l_m(t_e)}{1+(\Lambda_o-1)t_e}\right)^{\alpha} \qquad (40)

Derivation: dY/dte=θFTeFTc=(1α)tˉ1α[θ(le/te)α(lc/(1te))α]dY/dt_e = \theta F_T^e - F_T^c = (1-\alpha)\bar t^{1-\alpha}[\theta(l_e/t_e)^\alpha - (l_c/(1-t_e))^\alpha]. Substituting (36) at μ=1\mu=1 gives le/te=Λo(1lm)/Dol_e/t_e = \Lambda_o(1-l_m)/D_o and lc/(1te)=(1lm)/Dol_c/(1-t_e) = (1-l_m)/D_o with Do=1+(Λo1)teD_o = 1+(\Lambda_o-1)t_e, and θΛoα=Λo1αΛoα=Λo\theta\Lambda_o^\alpha = \Lambda_o^{1-\alpha}\Lambda_o^{\alpha} = \Lambda_o.

This is exactly z(te)z'(t_e) from Section 3 with the agricultural labor share (1lm)(1-l_m) in place of the whole labor force. Manufacturing changes the level but not the sign.

Two thresholds, not one. The sign of (40) is that of (Λo1)(\Lambda_o - 1), i.e. of (θ1)(\theta-1) — note Λo\Lambda_o, not Λμ\Lambda_\mu. This margin turns at θ=1\theta=1; the labor-allocation reversal of (39) turns at θHμ\theta_H^\mu. They answer different questions — is enclosure worth doing versus which way does it push labor — and must not be conflated. Below θ=1\theta=1 enclosure lowers output even at c=0c=0; at θ=1\theta=1 (40) is identically zero; above it the planner encloses while (40) exceeds ctˉc\,\bar t.

So teo=0t_e^o=0 for every c>0c>0 whenever θ1\theta\le1, however misallocated the decentralized economy’s labor is at te=0t_e=0. That full enclosure reproduces the planner’s labor allocation does not make full enclosure optimal. At θ=1\theta=1 in particular, the whole gain from enclosure is the repair of the commons distortion, which regulating the commons (μ1\mu\to1) achieves at te=0t_e=0 without incurring cTˉc\bar T.


Equation (41): Three Regimes

Since θHμ=[1μ(1α)]/α\theta_H^\mu = [1-\mu(1-\alpha)]/\alpha from (24) and the enclosure margin turns at θ=1\theta=1,

θHμ1=(1α)(1μ)α    0,with equality iff μ=1(41)\theta_H^\mu - 1 = \frac{(1-\alpha)(1-\mu)}{\alpha} \;\geq\; 0, \qquad \text{with equality iff } \mu=1 \qquad (41)

The two thresholds therefore bracket a band, and the parameter space divides into three regimes:

RegimeRangeEnclosure socially desirable?Effect on structural transformationEnclosure game
Aθ<1\theta<1No (at any c>0c>0)Releases labor to manufacturingComplements
B1<θ<θHμ1<\theta<\theta_H^\muYes, if cc small enoughReleases labor to manufacturingComplements
Cθ>θHμ\theta>\theta_H^\muYes, if cc small enoughDraws labor back into agricultureSubstitutes

Regime B is the configuration the conventional account of enclosure and industrialization presumes — enclosure both efficiency-improving and labor-releasing. By (41) its width is proportional to (1μ)(1-\mu), so it exists only to the extent that the commons is poorly governed, and closes entirely at μ=1\mu=1. It is also wider the larger is land’s share (1α)(1-\alpha). The conventional account is thus not a general property of enclosure but a feature of the open-access case, and one that yields an inverted comparative static: within B, the labor-release effect weakens as θ\theta rises toward θHμ\theta_H^\mu, so enclosures delivering the largest productivity gains should release the least labor.

The last column is not an additional assumption. By (12), rμ(te)r_\mu(t_e) is increasing in tet_e exactly when Λμ<1\Lambda_\mu<1 — the condition for strategic complementarity, and hence for the multiplicity that (15) resolves. By (39) that is also exactly the condition for enclosure to release labor. The two are the same inequality because both turn on whether enclosed land is more or less labor-hungry than the commons. Hence:

Wherever enclosure accelerates structural transformation, the enclosure game admits multiple equilibria; wherever it retards structural transformation, the equilibrium is unique.

Regimes A and B lie entirely inside the strategic-complements region and C entirely outside it. The enclosures relevant to industrialization are therefore precisely those whose extent is not pinned down by fundamentals alone.


Equation (42): Private Enclosure with Manufacturing and Compensation

Equations (40)–(41) describe what the planner would do. Restoring the decentralized enclosure condition (27) in the presence of manufacturing:

rμe(te)τrμc(te)=(1α)Alˉα(1lm(te)1+(Λμ1)te)α[θΛματ](42)r_\mu^e(t_e) - \tau\,r_\mu^c(t_e) = (1-\alpha)A\bar l^\alpha\left(\frac{1-l_m(t_e)}{1+(\Lambda_\mu-1)t_e}\right)^{\alpha}\Big[\theta\Lambda_\mu^{\alpha} - \tau\Big] \qquad (42)

Derivation: With manufacturing present, the enclosed and commons labor–land ratios are Le/Te=Λμ(1lm)lˉ/DμL_e/T_e = \Lambda_\mu(1-l_m)\bar l/D_\mu and Lc/Tc=(1lm)lˉ/DμL_c/T_c = (1-l_m)\bar l/D_\mu, with Dμ=1+(Λμ1)teD_\mu = 1+(\Lambda_\mu-1)t_e, by (36). Substituting into rμe=θ(1α)A(Le/Te)αr^e_\mu = \theta(1-\alpha)A(L_e/T_e)^\alpha and rμc=(1α)A(Lc/Tc)αr^c_\mu = (1-\alpha)A(L_c/T_c)^\alpha and collecting terms gives (42). The marginal encloser takes lml_m and the wage as given, so lml_m enters as a level, not through a strategic term.

The factorization is worth pausing on. Manufacturing enters only through (1lm)α(1-l_m)^\alpha — a scale factor common to both rentals, reflecting that a smaller agricultural labor force lowers the land–labor ratio and hence both rents equally. τ\tau enters only the bracket. The planner’s counterpart, from (40), is the bracket [Λo1][\Lambda_o-1]; since θΛμα=Λμ\theta\Lambda_\mu^\alpha = \Lambda_\mu when μ=1\mu=1, private and social margins coincide exactly at μ=1\mu=1 and τ=1\tau=1, which is the condition stated in §5.3.


Equation (43): The Compensation Threshold

From the bracket in (42), enclosure is privately profitable at some c0c \geq 0 if and only if

τ<τ(θ,μ)=θΛμα=θ11α(αAμ)α1α(43)\tau < \tau^*(\theta,\mu) = \theta\,\Lambda_\mu^{\alpha} = \theta^{\frac{1}{1-\alpha}}\left(\frac{\alpha}{A_\mu}\right)^{\frac{\alpha}{1-\alpha}} \qquad (43)

τ\tau^* is strictly increasing in both θ\theta and μ\mu. The second is a second-best tension in its own right: better commons governance raises Λμ\Lambda_\mu and hence the enclosed-land rent, so improving governance makes enclosure harder to deter by compensation, even as it makes deterrence more worthwhile.

Setting τ=1\tau^*=1 and solving gives the range over which full compensation binds at all:

τ(θ,μ)1    θ(θHμ)α\tau^*(\theta,\mu) \lessgtr 1 \iff \theta \lessgtr \left(\theta_H^\mu\right)^{\alpha}

Since θHμ1\theta_H^\mu \geq 1 and α<1\alpha<1, this lies strictly between 1 and θHμ\theta_H^\mu and collapses to 1 at μ=1\mu=1. Above it no admissible τ\tau prevents enclosure, and compensation is a pure transfer with no allocative consequence. This splits regime B of (41) at (θHμ)α(\theta_H^\mu)^\alpha into a sub-range where a compensation requirement blocks enclosure and one where it does not.

τ\tau moves neither threshold of (41). Appearing in neither production nor the planner’s objective, it cannot shift θHμ\theta_H^\mu or the θ=1\theta=1 margin. Its role is to select which tet_e is reached, not what enclosure does once there: μ\mu changes what enclosure would do, τ\tau changes whether it happens.

Consequently the two instruments are complements rather than substitutes, and Y/τ\partial Y/\partial \tau changes sign with μ\mu. Requiring compensation without regulating the commons removes the repair of the labor misallocation that enclosure was accomplishing; requiring it with a regulated commons prevents enclosure that would merely expend cc. This is the claim of §5.3, now with a second margin on which it operates. Worked numerical illustrations are in enclose/manufacturing.py.

Caveat. Any equilibrium tet_e computed from the marginal condition alone is incomplete for θ<θHμ\theta<\theta_H^\mu, where (15)'s refinement is needed to select among multiple equilibria.


[End of Section 6]

Interpretation of these results — the mapping from regimes to historical accounts of enclosure, the relation to dual-economy models, and the research agenda they suggest — is deliberately not developed here. See notes/manuf_paper_ideas.md in the project repository.


Appendix G: Computational Verification

All equations in this appendix have been implemented and can be verified using the Python module enclose.py located at notebooks/enclose.py.

G.1 Code Overview

The enclose.py module provides a complete computational implementation of the model with functions for:

Standard Parameters Used Throughout:


G.2 Function-to-Equation Mapping

Python FunctionEquationsPurposeKey Parameters
f(T, L, a, th)ProductionCobb-Douglas F(T,L)=T1αLαF(T,L) = T^{1-\alpha}L^\alphaα, θ
Lambda(th, alp, mu)(4), (10), (23)Compute Λ\Lambda parameterθ, α, μ
le(te, th, alp, mu)(4), (10), (23)Labor reaction function le(te)l_e(t_e)θ, α, μ
z(te, th, alp, lbar)(5)First-best output z1(te)z_1(t_e)θ, α, lˉ\bar{l}
zpv(te, th, alp, lbar)(17)Second-best output z0(te)z_0(t_e)θ, α, lˉ\bar{l}
req(te, th, alp, lbar, mu)(12), (27)Rental rate r(te)r(t_e) or rμ(te)r_\mu(t_e)θ, α, lˉ\bar{l}, μ
weq(te, th, alp, lbar, mu)Labor equilibriumCommons average product APLc(te)AP_L^c(t_e). The wage is AμA_\mu \cdot weq, per (37) — the two coincide only at μ=0\mu=0θ, α, lˉ\bar{l}, μ
zprime(te, th, alp, lbar, mu)(6), (7), (19), (20)Marginal benefit z(te)z'(t_e) or z0(te)z_0'(t_e)θ, α, lˉ\bar{l}, μ
teopt(th, alp, c, lbar)Lemma 1Optimal enclosure rate (first-best)θ, α, c, lˉ\bar{l}
tepvt(th, alp, c, lbar, mu)Props 2-3Private enclosure rateθ, α, c, lˉ\bar{l}, μ
tepvt_g(th, alp, c, lbar, mu)(15)Global games refined equilibriumθ, α, c, lˉ\bar{l}, μ
mple(te, le, a, th, lbar)SupportingMarginal product of labor (enclosed)
mpt(te, le, a, th, lbar)SupportingMarginal product of land
totalq(te, th, alp, lbar, mu)SupportingTotal economy output

The three-sector extension of §6.4 lives in a separate module, enclose/manufacturing.py in the open-enclose.github.io repository, with tests in tests/test_manufacturing.py:

Python FunctionEquationsPurposeKey Parameters
commons_wedge(alp, mu)(37)Governance wedge AμA_\muα, μ
mpl_m(lm, p, kb, b)(38)MPLmMP_L^m, manufacturing sidep, kˉ\bar k, β
mpl_a(lm, te, tbar, alp, th, mu)(38)Agricultural return AμAPLcA_\mu \cdot AP_L^c — a marginal product only at μ=1\mu=1α, θ, μ, tet_e
labor_share(te, ...)(39)Equilibrium lml_m, bracketed solveall
labor_share_closed_form(te, ...)(39)Exact lml_m at β=α\beta=\alpha; used as a test oracleall
agricultural_labor(te, ...)(36)leμ(te)l_e^\mu(t_e) with manufacturing presentθ, α, μ
total_output(te, ...)SupportingY/LˉY/\bar L at the equilibrium allocation, gross of ccall
planner_marginal_benefit(te, ...)(40)dY/dtedY/dt_e at the planner’s allocationα, θ, β, p
private_marginal_return(te, tau, ...)(42)rμeτrμcr^e_\mu - \tau r^c_\mu with manufacturingα, θ, β, μ, τ
compensation_threshold(th, alp, mu)(43)τ(θ,μ)\tau^*(\theta,\mu)α, θ, μ

Equation (37) is the correction most worth checking against: it was absent from earlier drafts of this material, which stated the μ=0\mu=0 shorthand of (38) as though it held for all μ\mu. tests/test_manufacturing.py pins it by verifying the planner’s first-order conditions against the primitive derivatives of the objective, independently of any expression in §6.4.


G.3 Figure References

All figures in the main paper were generated using the code and can be found in the docs/Figures/ directory:

Core Figures:

Extended Model Figures:

Note: If specific figures are not found, placeholder references are provided. Figures can be regenerated using:

import enclose as enc
import matplotlib.pyplot as plt

# Example: Plot rental rate function
te_vals = np.linspace(0, 1, 100)
r_vals = [enc.req(te, th=1.5, alp=2/3, ltbar=2.0, mu=0) for te in te_vals]
plt.plot(te_vals, r_vals)
plt.xlabel('$t_e$')
plt.ylabel('$r(t_e)$')
plt.title('Rental Rate Function')
plt.savefig('rental_rate.png')

G.4 Verification Examples

Example 1: Verify Equation (5)

import enclose as enc

# Parameters
th = 1.5
alp = 2/3
lbar = 2.0
te = 0.5

# Compute z_1(t_e) using closed form (equation 5)
Lambda_o = th**(1/(1-alp))
z1 = lbar**alp * (1 + (Lambda_o - 1) * te)**(1-alp)

# Verify using code
z1_code = enc.z(te, th, alp, lbar)

print(f"Equation (5): z_1({te}) = {z1:.6f}")
print(f"Code output: {z1_code:.6f}")
print(f"Match: {np.isclose(z1, z1_code)}")

Example 2: Verify Labor Allocation (Equation 10)

# Compute labor allocation
Lambda = (alp * th)**(1/(1-alp))
le_formula = (Lambda * te) / (1 + (Lambda - 1) * te)

# Using code
le_code = enc.le(te, th, alp, mu=0)

print(f"Equation (10): l_e({te}) = {le_formula:.6f}")
print(f"Code output: {le_code:.6f}")
print(f"Match: {np.isclose(le_formula, le_code)}")

Example 3: Verify Thresholds (Equations 6-7, 13-14)

# First-best thresholds
c = 1.0
A = 1.0

lbar0_1 = (c / (A * (1-alp) * (Lambda_o - 1)))**(1/alp)
lbar1_1 = Lambda_o * lbar0_1

# Decentralized thresholds
lbar0_d = (c / (th * A * (1-alp) * Lambda**alp))**(1/alp)
lbar1_d = (c / (th * A * (1-alp)))**(1/alp)

print(f"First-best: l̄₀¹ = {lbar0_1:.4f}, l̄₁¹ = {lbar1_1:.4f}")
print(f"Decentralized: l̄₀ᵈ = {lbar0_d:.4f}, l̄₁ᵈ = {lbar1_d:.4f}")

G.5 Reproducing Main Results

The key propositions can be verified computationally:

Proposition 1 (Strategic Interactions):

# Check sign of r'(t_e)
theta_H = 1 / alp  # Critical threshold
te_test = 0.5

# High-TFP case (strategic substitutes)
r_high_before = enc.req(te_test - 0.01, th=2.0, alp=alp, ltbar=lbar, mu=0)
r_high_after = enc.req(te_test + 0.01, th=2.0, alp=alp, ltbar=lbar, mu=0)
print(f"High-TFP: r'(t_e) < 0? {r_high_after < r_high_before}")

# Low-TFP case (strategic complements)
r_low_before = enc.req(te_test - 0.01, th=1.2, alp=alp, ltbar=lbar, mu=0)
r_low_after = enc.req(te_test + 0.01, th=1.2, alp=alp, ltbar=lbar, mu=0)
print(f"Low-TFP: r'(t_e) > 0? {r_low_after > r_low_before}")

Proposition 4 (Second-Best Concavity):

# Check concavity of z_0(t_e)
te_vals = np.linspace(0, 1, 100)
z0_vals = [enc.zpv(te, th=1.5, alp=alp, lbar=lbar) for te in te_vals]
z0_second_diff = np.diff(np.diff(z0_vals))
print(f"z_0 concave (high-TFP)? {np.all(z0_second_diff < 1e-6)}")

z0_vals_low = [enc.zpv(te, th=1.2, alp=alp, lbar=lbar) for te in te_vals]
z0_second_diff_low = np.diff(np.diff(z0_vals_low))
print(f"z_0 convex (low-TFP)? {np.all(z0_second_diff_low > -1e-6)}")

References for Computational Methods


Conclusion

This online appendix provides complete mathematical derivations for all equations in “A Model of Enclosures.” The derivations show how:

  1. First-best outcomes (Section 3.2) emerge from a social planner equalizing marginal products

  2. Decentralized decisions (Section 3.3) lead to labor misallocation due to open access

  3. Efficiency losses (Section 4) arise from two offsetting externalities

  4. Institutional parameters (Section 5) can improve outcomes but require coordinated reform

  5. Applications (Section 6) connect the framework to historical and contemporary settings

All results are computationally implemented and verified in the accompanying Python code at notebooks/enclose.py.


Document Prepared: February 2026 For: Submission to Review of Economic Studies Code repository: https://github.com/open-enclose/open-enclose.github.io