Hint Rewrite @sepcon_emp @emp_sepcon @TT_andp @andp_TT
@exp_sepcon1 @exp_sepcon2
@exp_andp1 @exp_andp2
@sepcon_andp_prop @sepcon_andp_prop'
using (solve [auto with typeclass_instances])
: norm.

Lemma imp_pred_ext  {A}  {NA: NatDed A}: forall B B' P Q,
(B <--> B') && (B --> (P <--> Q))
|-- (B --> P) <-->  (B' --> Q).