simp only [eval_imp] at h1
P Q : Formula
h1 : ∀ (V : VarBoolAssignment), evalPrime V (P.imp_ Q)
h2 : P.IsTautoPrime
⊢ Q.IsTautoPrime
P Q : Formula
h2 : P.IsTautoPrime
h1 : ∀ (V : VarBoolAssignment), evalPrime V P → evalPrime V Q
⊢ Q.IsTautoPrime