simp only [or_true, forall_true_left] at this
ψ : Formula
W : Type
M : KripkeModel W
w : W
α β : Program
Fs : List Formula
Fδ_in : (Fs, ε) ∈ H α
w_Con : ∀ (f : Formula), f ∈ Fs ∨ f = (~⌈β⌉ψ) → evaluate M w f
this : (~⌈β⌉ψ) ∈ Fs ∨ (~⌈β⌉ψ) = (~⌈β⌉ψ) → evaluate M w (~⌈β⌉ψ)
⊢ ∃ Gγ ∈ H β, evaluate M w (Con (Yset Gγ ψ))
ψ : Formula
W : Type
M : KripkeModel W
w : W
α β : Program
Fs : List Formula
Fδ_in : (Fs, ε) ∈ H α
w_Con : ∀ (f : Formula), f ∈ Fs ∨ f = (~⌈β⌉ψ) → evaluate M w f
this : evaluate M w (~⌈β⌉ψ)
⊢ ∃ Gγ ∈ H β, evaluate M w (Con (Yset Gγ ψ))