Definition table (A B : Type) := list (A*B).Fixpoint table_get {A B}{H: EqDec A} (rho: table A B) (x: A) : option B :=
  match rho with
  | (y,v)::ys => if eq_dec x y then Some v else table_get ys x
  | nil => None
 end.Definition table_set {A B}{H: EqDec A} (x: A) (v: B) (rho: table A B)  : table A B := (x,v)::rho.

Lemma table_gss {A B}{H: EqDec A}: forall rho x (v: B), table_get (table_set x v rho) x = Some v.