Section logic2.
Context {L : Type}.
Context {ILO : ILogicOps L}.
Context {IL : ILogic L}.
Definition liff (A B : L) : L :=
(A -->> B) //\\ (B -->> A).
Local Notation "x <<-->> y" := (liff x y) (at level 78).

Lemma land_limpl_specialize_ap : forall P Q L R G,
L //\\ R |-- P ->
L //\\ Q //\\ R |-- G ->
L //\\ (P -->> Q) //\\ R |-- G.