var c a k r;
varexo e;
parameters alpha beta sigma rho cs as ks rs;
alpha = 0.33;
beta = 0.99;
sigma = 2;
rho = 0.9;

model(linear);
cs*c + ks*k = rs*ks*r + (1+rs)*ks*k(-1);
c = c(+1) - (r(+1)/sigma)*(rs/(1+rs));
r = a + (alpha-1)*(k(-1));
a = rho*a(-1) + e;
end;

check;