Set: pp::colors
  Set: pp::unicode
proj1 (tuple 10, 20) : ℕ
10
20
tuple 20, 30
20
30
40
  Defined: NZ
  Assumed: t
proj1 t : ℕ
proj2 t : 1 ≤ proj1 t
  Assumed: t2
proj2 t2 : ℕ ⨯ ℕ