End CORESTEPS.

Lemma EFF_switch_descent:
forall cenv xenv k ls body s,
transl_lblstmt cenv (switch_env ls xenv) ls body = OK s ->
exists k',
transl_lblstmt_cont cenv xenv ls k k'
/\ (forall f sp e m,
effstep_plus cmin_eff_sem tge EmptyEffect
(CMin_State f s k sp e) m (CMin_State f body k' sp e) m).