Section COMBINE.
Variable ge: genv.
Variable sp: val.
Variable m: mem.
Variable get: valnum -> option rhs.
Variable valu: valuation.
Hypothesis get_sound: forall v rhs, get v = Some rhs -> rhs_eval_to valu ge sp m rhs (valu v).

Lemma get_op_sound:
forall v op vl, get v = Some (Op op vl) -> eval_operation ge sp op (map valu vl) m = Some (valu v).