Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply SNo_mul_SNo with
x0,
mul_SNo x1 x2 leaving 2 subgoals.
The subproof is completed by applying H0.
Apply SNo_mul_SNo with
x1,
x2 leaving 2 subgoals.
The subproof is completed by applying H1.
The subproof is completed by applying H2.