. intros Hne; simp [Hne]
case e
head mid : TensorElem
tail : List TensorElem
s_head : ℕ
s_tail head_shape : List ℕ
s_head' : ℕ
s_tail' : List ℕ
⊢ ¬head_shape = s_tail' →
    (if head_shape = s_tail' then some ((s_head' + 1) :: s_tail') else none) = some (s_head :: s_tail) →
      0 < s_head ∧ head_shape = s_tail ∧ s_head' = s_head - 1 ∧ s_tail' = s_tail
no goals