Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply and4I with
x0 ∈ int,
x1 ∈ int,
x2 ∈ int,
∃ x3 . and (x3 ∈ int) (∃ x4 . and (x4 ∈ int) (add_SNo (mul_SNo x3 x0) (mul_SNo x4 x1) = x2)) leaving 2 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.