|- !P. (!m n. n <= m ==> P n) ==> (!m. P m)
|- !m n. n <= m = n < SUC m
|- !P. (!m. (!n. n < m ==> P n) ==> P m) ==> (!m n. n <= m ==> P n)
|- !P. (!m. (!n. n < m ==> P n) ==> P m) ==> (!m. P m)