case nil =>
  cases ys
  case nil =>
    simp
  case cons ys_hd ys_tl =>
    simp only [isAlphaEqvVarList] at h2
D : Type
binders : List (VarName × VarName)
V V' : VarAssignment D
h1 : AlphaEqvVarAssignment D binders V V'
ys : List VarName
h2 : isAlphaEqvVarList binders [] ys
⊢ List.map V [] = List.map V' ys
no goals