Notation corestepN := (corestepN (AsmContext.coarse_semantics initU)).

Lemma safety_det_corestepN_internal:
forall xs i U tpc trc mc tpc' mc' fuelF
(Hsafe : csafe ((i :: U),trc,tpc) mc
(fuelF.+1 + size xs))
(Hexec : internal_execution [seq x <- xs | x == i] tpc mc tpc' mc'),
exists trc',
corestepN (size [seq x <- xs | x == i])
((i :: U), trc, tpc) mc ((i :: U), trc ++ trc', tpc') mc'
/\ csafe ((i :: U),trc ++ trc',tpc') mc'
(fuelF.+1 + size [seq x <- xs | x != i]).