rw [Order.lex_impl]
n : ℕ
a : Variables n order.Lex
m : ℕ
v : Variables m order.Lex
p : List.length [] = m
⊢ Order.lex_impl { val := [], property := p } { val := [], property := p }
n : ℕ
a : Variables n order.Lex
m : ℕ
v : Variables m order.Lex
p : List.length [] = m
⊢ match { val := [], property := p }, { val := [], property := p } with
  | { val := [], property := property }, { val := [], property := property_1 } => True
  | { val := x :: tail, property := property }, { val := y :: tail_1, property := property_1 } =>
    if x = y then Order.lex_impl (Vector.tail { val := [], property := p }) (Vector.tail { val := [], property := p })
    else x ≤ y