  For piecewise $C^1$ interval maps possibly containing critical points and
discontinuities with negative Schwarzian derivative, under two summability
conditions on the growth of the derivative and recurrence along critical
orbits, we prove the nonexistence of wandering intervals, the existence of
absolutely continuous invariant measures, and the bounded backward contraction
property. The proofs are based on the method of proving the existence of
absolutely continuous invariant measures of unimodal map, developed by Nowicki
and van Strien.
