fact: Definition step_star_lb_step_reachable (lb_step : lb_step_relation) (step : step_relation A trace) (init : A) := forall a l a' tr tr', refl_trans_1n_trace step init a tr' -> lb_step a l a' tr -> refl_trans_1n_trace step init a' (tr' ++ tr).
imports: Verdi(Verdi) InfSeqExt(infseq exteq) Verdi(Ssrexport)