use Y
case cons.mpr.intro.intro.inr.h
W : Type
M : KripkeModel W
w : W
N : ℕ
X : List Formula
XS : List (List Formula)
IH : Evaluate (M, w) (discon XS) ↔ ∃ Y ∈ XS, ∀ f ∈ Y, Evaluate (M, w) f
Y : List Formula
Ysat : ∀ f ∈ Y, Evaluate (M, w) f
h✝ : Y ∈ XS
⊢ ∃ Y ∈ XS, ∀ f ∈ Y, Evaluate (M, w) f
no goals