let T be T_0-TopSpace; ( InclPoset the topology of T is continuous implies S6[T] )
assume A1:
InclPoset the topology of T is continuous
; S6[T]
let S be Scott TopAugmentation of InclPoset the topology of T; for y being Element of T
for V being open a_neighborhood of y ex H being open Subset of S st
( V in H & meet H is a_neighborhood of y )
let y be Element of T; for V being open a_neighborhood of y ex H being open Subset of S st
( V in H & meet H is a_neighborhood of y )
let V be open a_neighborhood of y; ex H being open Subset of S st
( V in H & meet H is a_neighborhood of y )
A2:
( Int V c= V & y in Int V )
by CONNSP_2:def 1, TOPS_1:16;
V in the topology of T
by PRE_TOPC:def 2;
then reconsider W = V as Element of (InclPoset the topology of T) by YELLOW_1:1;
W =
sup (waybelow W)
by A1, WAYBEL_3:def 5
.=
union (waybelow W)
by YELLOW_1:22
;
then consider Z being set such that
A3:
y in Z
and
A4:
Z in waybelow W
by A2, TARSKI:def 4;
reconsider Z = Z as Element of (InclPoset the topology of T) by A4;
A5:
RelStr(# the carrier of (InclPoset the topology of T), the InternalRel of (InclPoset the topology of T) #) = RelStr(# the carrier of S, the InternalRel of S #)
by YELLOW_9:def 4;
then reconsider Z1 = Z as Element of S ;
Z in the carrier of (InclPoset the topology of T)
;
then
Z in the topology of T
by YELLOW_1:1;
then reconsider Z2 = Z as open Subset of T by PRE_TOPC:def 2;
A6:
Z c= meet (uparrow Z)
reconsider H = wayabove Z1 as open Subset of S by A1, WAYBEL11:36;
take
H
; ( V in H & meet H is a_neighborhood of y )
Z << W
by A4, WAYBEL_3:7;
then A9:
V in wayabove Z
;
hence A10:
V in H
by A5, YELLOW12:13; meet H is a_neighborhood of y
meet H c= the carrier of T
then reconsider mH = meet H as Subset of T ;
meet (uparrow Z) c= meet (wayabove Z)
by A9, SETFAM_1:6, WAYBEL_3:11;
then
meet (uparrow Z) c= meet (wayabove Z1)
by A5, YELLOW12:13;
then
Z2 c= mH
by A6;
then
Z2 c= Int mH
by TOPS_1:24;
hence
meet H is a_neighborhood of y
by A3, CONNSP_2:def 1; verum