let N be non empty MetrStruct ; :: thesis: ( N is Reflexive & N is triangle & TopSpaceMetr N is compact implies N is totally_bounded )
assume A1:
N is Reflexive
; :: thesis: ( not N is triangle or not TopSpaceMetr N is compact or N is totally_bounded )
assume A2:
N is triangle
; :: thesis: ( not TopSpaceMetr N is compact or N is totally_bounded )
set TM = TopSpaceMetr N;
A3:
TopSpaceMetr N = TopStruct(# the carrier of N,(Family_open_set N) #)
by PCOMPS_1:def 6;
assume A4:
TopSpaceMetr N is compact
; :: thesis: N is totally_bounded
let r be Real; :: according to TBSP_1:def 1 :: thesis: ( r > 0 implies ex G being Subset-Family of N st
( G is finite & the carrier of N = union G & ( for C being Subset of N st C in G holds
ex w being Element of N st C = Ball w,r ) ) )
assume A5:
r > 0
; :: thesis: ex G being Subset-Family of N st
( G is finite & the carrier of N = union G & ( for C being Subset of N st C in G holds
ex w being Element of N st C = Ball w,r ) )
defpred S1[ Subset of N] means ex x being Element of N st $1 = Ball x,r;
consider G being Subset-Family of N such that
A6:
for C being Subset of N holds
( C in G iff S1[C] )
from SUBSET_1:sch 3();
reconsider G = G as Subset-Family of (TopSpaceMetr N) by A3;
for C being Subset of (TopSpaceMetr N) st C in G holds
C is open
then A8:
G is open
by TOPS_2:def 1;
G is Cover of (TopSpaceMetr N)
then consider H being Subset-Family of (TopSpaceMetr N) such that
A10:
( H c= G & H is Cover of (TopSpaceMetr N) & H is finite )
by A4, A8, COMPTS_1:def 3;
reconsider H = H as Subset-Family of N by A3;
take
H
; :: thesis: ( H is finite & the carrier of N = union H & ( for C being Subset of N st C in H holds
ex w being Element of N st C = Ball w,r ) )
union H =
[#] (TopSpaceMetr N)
by A10, SETFAM_1:60
.=
the carrier of (TopSpaceMetr N)
;
hence
( H is finite & the carrier of N = union H & ( for C being Subset of N st C in H holds
ex w being Element of N st C = Ball w,r ) )
by A3, A6, A10; :: thesis: verum