2.6 The representative agent model
In the representative-agent Ramsey model we are, of course, unable to model pensions
and to differentiate between working hours and effective labor input. Everything else
is unchanged.
The representative household maximizes his infinite life-time utility
X βtu(ct, Mt/Pt, 1 - nt)
subject to
kt+1 + Mt+1 = (1 - δ + rt(1 - τ[(πt∕π)(wtnt + rtkt)]))kt
Pt
+ -+ + (1 - τ[(∏t/π)(wtnt + rtkt)])wtnt + trt + Ωt - ct.
Pt
His decision variables in period t = 0 are M1, k1, c0, and n0.
In this model, there are two predetermined state variables, the stock of capital kt and
beginning-of-period real money balances
mt := Mt/Pt-1 ^ Mt = —,∏t := pl-. (24)
Pt πt Pt-1
Using these definitions, we can write the first-order conditions as follows:
Mt
λt — uc ct, p , 1
nt) = Y (Ct)γ(1 σ) 1 (mt∕πt)(1 γ)(1 σ)
(25a)
λt = βEtλt +1 (1 - δ + rt +1(1 - τ0[(∏t∕π)(Wtnt + rtkt)](∏t∕∏))) ,
(25b)
λt = βE
Mt+1
λt+1 + ■ 'c" , -- ,
1 - nt+1)
πt+1
πt+1
(25c)
= βE
λt+1 + (1 - γ ) ( ct+1)γ (1 σ )
πt+1
(1-γ)(1-σ)-1
( mt +1 ∕πt +1)
πt+1
(25d)
Mt 1
un ct,p , 1
n-t^ = ηo(1 - nt) η = λtwt (1 - τ0 [(∏t∕π)(wtnt + rtkt)](πt∕π)).
(25e)
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