let T be non empty TopSpace; :: thesis: ( T is regular & InclPoset the topology of T is continuous implies T is locally-compact )
set L = InclPoset the topology of T;
A1:
InclPoset the topology of T = RelStr(# the topology of T,(RelIncl the topology of T) #)
by YELLOW_1:def 1;
assume A2:
( T is regular & InclPoset the topology of T is continuous )
; :: thesis: T is locally-compact
then A3:
InclPoset the topology of T is continuous LATTICE
;
let x be Point of T; :: according to WAYBEL_3:def 9 :: thesis: for X being Subset of T st x in X & X is open holds
ex Y being Subset of T st
( x in Int Y & Y c= X & Y is compact )
let X be Subset of T; :: thesis: ( x in X & X is open implies ex Y being Subset of T st
( x in Int Y & Y c= X & Y is compact ) )
assume A4:
( x in X & X is open )
; :: thesis: ex Y being Subset of T st
( x in Int Y & Y c= X & Y is compact )
then reconsider a = X as Element of (InclPoset the topology of T) by A1, PRE_TOPC:def 5;
a =
sup (waybelow a)
by A3, Def5
.=
union (waybelow a)
by YELLOW_1:22
;
then consider Y being set such that
A5:
( x in Y & Y in waybelow a )
by A4, TARSKI:def 4;
Y in the carrier of (InclPoset the topology of T)
by A5;
then reconsider Y = Y as Subset of T by A1;
consider y being Element of (InclPoset the topology of T) such that
A6:
( Y = y & y << a )
by A5;
Y is open
by A1, A5, PRE_TOPC:def 5;
then consider W being open Subset of T such that
A7:
( x in W & Cl W c= Y )
by A2, A5, URYSOHN1:29;
take Z = Cl W; :: thesis: ( x in Int Z & Z c= X & Z is compact )
W c= Z
by PRE_TOPC:48;
hence
x in Int Z
by A7, TOPS_1:54; :: thesis: ( Z c= X & Z is compact )
y <= a
by A6, Th1;
then
Y c= X
by A6, YELLOW_1:3;
hence
Z c= X
by A7, XBOOLE_1:1; :: thesis: Z is compact
let F be Subset-Family of T; :: according to COMPTS_1:def 7 :: thesis: ( not F is Cover of Z or not F is open or ex b1 being Element of K10(K10(the carrier of T)) st
( b1 c= F & b1 is Cover of Z & b1 is finite ) )
assume A8:
( F is Cover of Z & F is open )
; :: thesis: ex b1 being Element of K10(K10(the carrier of T)) st
( b1 c= F & b1 is Cover of Z & b1 is finite )
reconsider ZZ = {(Z ` )} as Subset-Family of T ;
reconsider ZZ = ZZ as Subset-Family of T ;
reconsider FZ = F \/ ZZ as Subset-Family of T ;
for x being Subset of T st x in ZZ holds
x is open
by TARSKI:def 1;
then
ZZ is open
by TOPS_2:def 1;
then
FZ is open
by A8, TOPS_2:20;
then reconsider FF = FZ as Subset of (InclPoset the topology of T) by YELLOW_1:25;
A9: sup FF =
union FZ
by YELLOW_1:22
.=
(union F) \/ (union ZZ)
by ZFMISC_1:96
.=
(union F) \/ (Z ` )
by ZFMISC_1:31
;
Z c= union F
by A8, SETFAM_1:def 12;
then
Z \/ (Z ` ) c= sup FF
by A9, XBOOLE_1:9;
then
[#] T c= sup FF
by PRE_TOPC:18;
then
X c= sup FF
by XBOOLE_1:1;
then
a <= sup FF
by YELLOW_1:3;
then consider A being finite Subset of (InclPoset the topology of T) such that
A10:
( A c= FF & y <= sup A )
by A6, Th18;
A11:
sup A = union A
by YELLOW_1:22;
reconsider G = A \ ZZ as Subset-Family of T by A1, XBOOLE_1:1;
take
G
; :: thesis: ( G c= F & G is Cover of Z & G is finite )
thus
G c= F
by A10, XBOOLE_1:43; :: thesis: ( G is Cover of Z & G is finite )
thus
Z c= union G
:: according to SETFAM_1:def 12 :: thesis: G is finite
thus
G is finite
; :: thesis: verum