# Time varying mark up

Dear Doctor Pfeifer

I am a Beginner at Dynare and I would like to write the price setting equation with time varying mark up using exp notation. With constant price mark up( theta_p ), the price setting with positive trend inflation (pi) and indexation (gammap) can be written in the following recursive way:

% (1)Reset price
exp(pr) = (1+theta_p)*exp(g1)/exp(g2));

% (2) Auxiliary g1
exp(g1) = exp(lam)exp(mc)exp(y) + xipbeta(exp(pi)^(gammap)/exp(pi(+1)))^(-(1+1/theta_p))*exp(g1(+1));

% (3) Auxiliary g2
exp(g2) = exp(lam)exp(y) + xipbeta*(exp(pi)^(gammap)/exp(pi(+1)))^(- 1/theta_p)*exp(g2(+1));

But I donâ€™t know how to write the same set of equation when I have mark up that follow, for example, an AR(1)process such ln(theta_p)=(1-rho)ln(theta_pp_ss)+ rho (ln(theta_p(-1))+eps.

Should I write exp(theta_p) or theta_p?

Thank you in advance for your help.

See [How to include an integral in dynare code?). With a time-varying markups, there is no recursive representation as far as I know.

Thank you very much Professor.