tauto
case h
v u x : VarName
phi : Formula
phi_ih : ∀ (binders : Finset VarName), ¬isBoundIn u phi → u ∉ binders → fastAdmitsAux v u binders phi
binders : Finset VarName
h2 : u ∉ binders
h1_left : u ≠ x
h1_right : ¬isBoundIn u phi
⊢ u ∉ binders ∧ ¬u = x
no goals