let x, y be Element of S; WAYBEL_1:def 2 ( not x <= y or (incl (S,R)) . x <= (incl (S,R)) . y )
reconsider a = x, b = y as Element of R by YELLOW_0:58;
the carrier of S c= the carrier of R
by YELLOW_0:def 13;
then A1:
incl (S,R) = id the carrier of S
by Def1;
then A2:
(incl (S,R)) . x = a
;
(incl (S,R)) . y = b
by A1;
hence
( not x <= y or (incl (S,R)) . x <= (incl (S,R)) . y )
by A2, YELLOW_0:59; verum