Hint Resolve regs_erasure_get regs_erasure_refl regs_erasure_set
: regs_erasure.
Notation the_ge := (@the_ge the_program).
(** ** Result about at_external, after_external and initial_core *)

Lemma undef_regs_comm:
forall regs rs r,
undef_regs regs (rs # r <- Vundef) =
(undef_regs regs rs) # r <- Vundef.