simp only [admitsAux] at h2
case def_
v u : VarName
a✝¹ : DefName
a✝ : List VarName
binders : Finset VarName
h1 : v ∉ binders
h2 : admitsAux v u binders (def_ a✝¹ a✝)
⊢ fastAdmitsAux v u binders (def_ a✝¹ a✝)
case def_
v u : VarName
a✝¹ : DefName
a✝ : List VarName
binders : Finset VarName
h1 : v ∉ binders
h2 : v ∈ a✝ ∧ v ∉ binders → u ∉ binders
⊢ fastAdmitsAux v u binders (def_ a✝¹ a✝)