| m0 < 5, ∀ m1, char. m1 < ((((m0 + 1) + 1) + 1) + 1) + 1 → true → ¬ char ∈ '0' + '1' + '2' + '3' + '4' + '5' + '6' + '7' + ('8' + '9') → ¬ char ∈ s→l(n→s(m1)) ⊦ m0 = 0, ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '1', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '2', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '3', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '4', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '5', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '6', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '7', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '8', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '9', ('6' ' + '7' ' + '8' ' + '9' ')[m0 - 1] = '0' |
m0 = m + 1, m0 < 5, ∀ m1, char. m1 < ((((m0 + 1) + 1) + 1) + 1) + 1 → true → ¬ char ∈ '0' + '1' + '2' + '3' + '4' + '5' + '6' + '7' + ('8' + '9') → ¬ char ∈ s→l(n→s(m1)) ⊦ m0 = 0, ('6' ' + '7' ' + '8' ' + '9' ')[m] = '1', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '2', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '3', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '4', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '5', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '6', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '7', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '8', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '9', ('6' ' + '7' ' + '8' ' + '9' ')[m] = '0'
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: m0, m