Would this be a recurrence problem?
I.
`Subscript[X, t] == (1 - \[Theta])*Sum[\[Theta]^(k - 1)*(Subscript[P, t - k] - Subscript[P, t - k - 1]),`
II.
`<{k, 1, t - 1}] + \[Theta]^(t - 1)*1,`
III. `
Subscript[NN, t] == Subscript[X, t]/(\[Gamma]*\[Sigma]^2),`
IV.
`Subscript[M, t] == (Subscript[D, t] - (T - t - 1)*\[Gamma]*\[Sigma]^2*Q - Subscript[P, t])/(\[Gamma]* \[Sigma]^2),
V.
EE*Subscript[NN, t] + FF*Subscript[MM, t] == Q,
V. `
EE == FF - 1`
I would like to solve this for Subscript[P, t]