Hi,

I am trying to use a simple seignioriage model to analyze MMT. After creating my model I am getting the error “Index in position 1 is invalid. Array indices must be positive inters or logical values”. I don’t know what this error means but any help would be appreciated.

```
% Variables
var p, T, N;
varexo G, B;
parameters mu, n;
% Calibration
mu=0.12;
n=0.03;
model;
1+p=(1+mu)/(1+n)*(T/T(+1));
G=B+mu/(1+mu)*N+T;
N(+1)=(1+n)*N;
end;
initval;
p=0.02;
T=0.357;
G=2;
B=1;
N=6;
end;
steady;
shocks;
var G;
periods 0:50, 51:200;
values 2, 4;
var B;
periods 0:50, 51:200;
values 1, 2;
end;
endval;
G=2;
B=1;
end;
steady;
perfect_foresight_setup(periods=200);
perfect_foresight_solver;
display(p);
subplot(2,3,1);plot(p);title('Inflation')
subplot(2,3,2);plot(T);title('Taxes')
subplot(2,3,3);plot(B);title('Debt')
subplot(2,3,4);plot(N);title('Population')```
```