n : ℕ
⊢ ↑(cast (_ : n = n)) = ↑(cast (_ : n = n))
n m : ℕ
h : n = m
⊢ ↑(cast h) = ↑(cast (_ : n = m))
subst h
case h.h
n : ℕ
x✝ : Fin n
⊢ ↑(↑(cast (_ : n = n)) x✝) = ↑(↑(cast (_ : n = n)) x✝)
n : ℕ
⊢ ↑(cast (_ : n = n)) = ↑(cast (_ : n = n))
ext
no goals
case h.h
n : ℕ
x✝ : Fin n
⊢ ↑(↑(cast (_ : n = n)) x✝) = ↑(↑(cast (_ : n = n)) x✝)
simp