let X be set ; for c being Function of (BoolePoset X),(BoolePoset X) st c is idempotent & c is directed-sups-preserving holds
inclusion c is directed-sups-preserving
let c be Function of (BoolePoset X),(BoolePoset X); ( c is idempotent & c is directed-sups-preserving implies inclusion c is directed-sups-preserving )
assume A1:
( c is idempotent & c is directed-sups-preserving )
; inclusion c is directed-sups-preserving
now let Y be
Ideal of
(Image c);
inclusion c preserves_sup_of Ynow
"\/" Y,
(BoolePoset X) in the
carrier of
(BoolePoset X)
;
then
"\/" Y,
(BoolePoset X) in dom c
by FUNCT_2:def 1;
then A2:
c . ("\/" Y,(BoolePoset X)) in rng c
by FUNCT_1:def 5;
Y c= the
carrier of
(Image c)
;
then A3:
Y c= rng c
by YELLOW_0:def 15;
reconsider Y9 =
Y as non
empty directed Subset of
(BoolePoset X) by YELLOW_2:7;
assume
ex_sup_of Y,
Image c
;
( ex_sup_of (inclusion c) .: Y, BoolePoset X & sup ((inclusion c) .: Y) = (inclusion c) . (sup Y) )A4:
ex_sup_of Y,
BoolePoset X
by YELLOW_0:17;
c preserves_sup_of Y9
by A1, WAYBEL_0:def 37;
then
"\/" (c .: Y),
(BoolePoset X) in rng c
by A4, A2, WAYBEL_0:def 31;
then
"\/" Y,
(BoolePoset X) in rng c
by A1, A3, YELLOW_2:22;
then A5:
"\/" Y,
(BoolePoset X) in the
carrier of
(Image c)
by YELLOW_0:def 15;
thus
ex_sup_of (inclusion c) .: Y,
BoolePoset X
by YELLOW_0:17;
sup ((inclusion c) .: Y) = (inclusion c) . (sup Y)thus sup ((inclusion c) .: Y) =
"\/" Y,
(BoolePoset X)
by FUNCT_1:162
.=
sup Y
by A4, A5, YELLOW_0:65
.=
(inclusion c) . (sup Y)
by TMAP_1:91
;
verum end; hence
inclusion c preserves_sup_of Y
by WAYBEL_0:def 31;
verum end;
hence
inclusion c is directed-sups-preserving
by WAYBEL_0:73; verum