have h4 : m = 1 := h1.eq_imp_1
case inl
N : ℕ
m : ℤ
h1 : ProblemPredicate N m m
h2 : 1 < m
⊢ ProblemPredicate N (m - m) m
case inl
N : ℕ
m : ℤ
h1 : ProblemPredicate N m m
h2 : 1 < m
h4 : m = 1
⊢ ProblemPredicate N (m - m) m