Set: pp::colors
  Set: pp::unicode
  Assumed: x
Type
ℤ → ℤ → ℤ
x1 + x2
ℤ → ℤ
x1 + x1 + x1 + x2 + x2
ℤ
Definition sum1 : ℤ := x1 + x1 + x1 + x2 + x2
x1 + x1 + x1 + x2 + x2
  Assumed: y