let S, T be non empty reflexive antisymmetric up-complete RelStr ; for X being Subset of st X is inaccessible_by_directed_joins holds
( proj1 X is inaccessible_by_directed_joins & proj2 X is inaccessible_by_directed_joins )
let X be Subset of ; ( X is inaccessible_by_directed_joins implies ( proj1 X is inaccessible_by_directed_joins & proj2 X is inaccessible_by_directed_joins ) )
assume A1:
for D being non empty directed Subset of st sup D in X holds
D meets X
; WAYBEL11:def 1 ( proj1 X is inaccessible_by_directed_joins & proj2 X is inaccessible_by_directed_joins )
A2:
the carrier of [:S,T:] = [:the carrier of S,the carrier of T:]
by YELLOW_3:def 2;
hereby WAYBEL11:def 1 proj2 X is inaccessible_by_directed_joins
let D be non
empty directed Subset of ;
( sup D in proj1 X implies D meets proj1 X )assume
sup D in proj1 X
;
D meets proj1 Xthen consider t being
set such that A3:
[(sup D),t] in X
by RELAT_1:def 4;
A4:
t in the
carrier of
T
by A2, A3, ZFMISC_1:106;
then reconsider t' =
{t} as non
empty directed Subset of
by WAYBEL_0:5;
ex_sup_of [:D,t':],
[:S,T:]
by WAYBEL_0:75;
then sup [:D,t':] =
[(sup (proj1 [:D,t':])),(sup (proj2 [:D,t':]))]
by YELLOW_3:46
.=
[(sup D),(sup (proj2 [:D,t':]))]
by FUNCT_5:11
.=
[(sup D),(sup t')]
by FUNCT_5:11
.=
[(sup D),t]
by A4, YELLOW_0:39
;
then
[:D,{t}:] meets X
by A1, A3;
then consider x being
set such that A5:
x in [:D,{t}:]
and A6:
x in X
by XBOOLE_0:3;
hence
D meets proj1 X
by XBOOLE_0:3;
verum
end;
let D be non empty directed Subset of ; WAYBEL11:def 1 ( not "\/" D,T in proj2 X or not D misses proj2 X )
assume
sup D in proj2 X
; not D misses proj2 X
then consider s being set such that
A7:
[s,(sup D)] in X
by RELAT_1:def 5;
A8:
s in the carrier of S
by A2, A7, ZFMISC_1:106;
then reconsider s' = {s} as non empty directed Subset of by WAYBEL_0:5;
ex_sup_of [:s',D:],[:S,T:]
by WAYBEL_0:75;
then sup [:s',D:] =
[(sup (proj1 [:s',D:])),(sup (proj2 [:s',D:]))]
by YELLOW_3:46
.=
[(sup s'),(sup (proj2 [:s',D:]))]
by FUNCT_5:11
.=
[(sup s'),(sup D)]
by FUNCT_5:11
.=
[s,(sup D)]
by A8, YELLOW_0:39
;
then
[:{s},D:] meets X
by A1, A7;
then consider x being set such that
A9:
x in [:{s},D:]
and
A10:
x in X
by XBOOLE_0:3;
hence
not D misses proj2 X
by XBOOLE_0:3; verum