Ramsey Problem with Two or More Social Planners

Hello, I’m trying to solve an Open Economy model with optimal Ramsey policy.
I want to compare cooperative versus strategic schemes. For that, there are cases where I
have more than one planner objective function (one per country each with its instrument).

Can I have multiple planner functions and solve the model? and if so, how should I state it?.
I was declaring the functions as follows:

// Objective function and discount factor

planner_objective C^(1-eta)/(1-eta) + a*G^(1-phi)/(1-phi) ;
ramsey_model(instruments=(TAU), planner_discount=beta);

planner_objective Cf^(1-eta)/(1-eta) + a*Gf^(1-phi)/(1-phi) ;
ramsey_model(instruments=(TAUf), planner_discount=beta);

However, I’m not getting a solution, just an error. (Error using print_info (line 54)
One of the eigenvalues is close to 0/0 (the absolute value of numerator and
denominator is smaller than 1e-06!)

On the other hand, the Cooperative case runs without problem:

planner_objective 1/2*(C^(1-eta)/(1-eta) + a*G^(1-phi)/(1-phi)) + 1/2 * (Cf^(1-eta)/(1-eta) + a*Gf^(1-phi)/(1-phi)) ;
ramsey_model(instruments=(TAU, TAUf), planner_discount=beta);

Thanks in advance for any reply!

_*this model is just a trivial extension of the closed econ in which I’m just adding the foreign variables and assuming autarky. It’s not the actual one I wanna compare _
Nash vs. Cooperation but I want to have a working knowledge of the solution method (even if it’s qualitatively purposeless in this cae) in dynare before implementing an actual open econ model with cross country externalities.

example_ramsey_open_attempt.mod (2.3 KB)

Dynare does not allow you to do this. Some of the issues arising have been discussed at