Section Restrict.
Variables (T : finType) (x : T).
Notation T' := {y | y != x}.
Definition rfd_fun p := [fun u => Sub ((_ : {perm T}) _) (rfd_funP p u) : T'].
Definition rfd p := perm (@rfdP p).
Hypothesis card_T : 2 < #|T|.

Lemma rfd_morph : {in 'C_('Sym_T)[x | 'P] &, {morph rfd : y z / y * z}}.