| m < 10, ∀ m1. m1 < m → true → s→n(n→s(m1)) = m1 ⊦ pos (('0' ' + '1' ' + '2' ' + '3' ' + '4' ' + '5' ' + '6' ' + '7' ' + '8' ' + '9' ')[m], '0' + '1' + '2' + '3' + '4' + '5' + '6' + '7' + ('8' + '9')) = m |
m < 10, ∀ m1. m1 < m → true → s→n(n→s(m1)) = m1 ⊦ pos (('0' ' + '1' ' + '2' ' + '3' ' + '4' ' + '5' ' + '6' ' + '7' ' + '8' ' + '9' ')[m], '0' ' + '1' ' + '2' ' + '3' ' + '4' ' + '5' ' + '6' ' + '7' ' + '8' ' + '9' ') = m
Used simplifier rules: c: ⊦ char + chars = char ' + chars; from specification list[charlist]%Two: ⊦ char + char0 = char ' + char0 '; from specification list[charlist]