  We obtain results on mixing for a large class of (not necessarily Markov)
infinite measure semiflows and flows. Erickson proved, amongst other things, a
strong renewal theorem in the corresponding i.i.d. setting. Using operator
renewal theory, we extend Erickson's methods to the deterministic (i.e.
non-i.i.d.) continuous time setting and obtain results on mixing as a
consequence.
  Our results apply to intermittent semiflows and flows of Pomeau-Manneville
type (both Markov and nonMarkov), and to semiflows and flows over
Collet-Eckmann maps with nonintegrable roof function.
