Theorem cnextucn 22107

Description: Extension by continuity. Proposition 11 of [BourbakiTop1] p. II.20. Given a topology J on X, a subset A dense in X, this states a condition for F from A to a space Y Hausdorff and complete to be extensible by continuity. (Contributed by Thierry Arnoux, 4-Dec-2017.)

Hypotheses

Ref	Expression
cnextucn.x	|- X = ( Base ` V )
cnextucn.y	|- Y = ( Base ` W )
cnextucn.j	|- J = ( TopOpen ` V )
cnextucn.k	|- K = ( TopOpen ` W )
cnextucn.u	|- U = (UnifSt ` W )
cnextucn.v	|- ( ph -> V e. TopSp )
cnextucn.t	|- ( ph -> W e. TopSp )
cnextucn.w	|- ( ph -> W e. CUnifSp )
cnextucn.h	|- ( ph -> K e. Haus )
cnextucn.a	|- ( ph -> A C_ X )
cnextucn.f	|- ( ph -> F : A --> Y )
cnextucn.c	|- ( ph -> ( ( cls ` J ) ` A ) = X )
cnextucn.l	|- ( ( ph /\ x e. X ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. (CauFilu ` U ) )

Assertion

Ref	Expression
cnextucn	|- ( ph -> ( ( JCnExt K ) ` F ) e. ( J Cn K ) )

Distinct variable groups:   x, A   x, F   x, J   x, K   ph, x

Allowed substitution hints:   U( x)   V( x)   W( x)   X( x)   Y( x)

Proof of Theorem cnextucn

Step	Hyp	Ref	Expression
1		eqid 2622	. 2 |- U. J = U. J
2		eqid 2622	. 2 |- U. K = U. K
3		cnextucn.v	. . 3 |- ( ph -> V e. TopSp )
4		cnextucn.j	. . . 4 |- J = ( TopOpen ` V )
5	4	tpstop 20741	. . 3 |- ( V e. TopSp -> J e. Top )
6	3, 5	syl 17	. 2 |- ( ph -> J e. Top )
7		cnextucn.h	. 2 |- ( ph -> K e. Haus )
8		cnextucn.f	. . 3 |- ( ph -> F : A --> Y )
9		cnextucn.t	. . . . 5 |- ( ph -> W e. TopSp )
10		cnextucn.y	. . . . . 6 |- Y = ( Base ` W )
11		cnextucn.k	. . . . . 6 |- K = ( TopOpen ` W )
12	10, 11	tpsuni 20740	. . . . 5 |- ( W e. TopSp -> Y = U. K )
13	9, 12	syl 17	. . . 4 |- ( ph -> Y = U. K )
14	13	feq3d 6032	. . 3 |- ( ph -> ( F : A --> Y <-> F : A --> U. K ) )
15	8, 14	mpbid 222	. 2 |- ( ph -> F : A --> U. K )
16		cnextucn.a	. . 3 |- ( ph -> A C_ X )
17		cnextucn.x	. . . . 5 |- X = ( Base ` V )
18	17, 4	tpsuni 20740	. . . 4 |- ( V e. TopSp -> X = U. J )
19	3, 18	syl 17	. . 3 |- ( ph -> X = U. J )
20	16, 19	sseqtrd 3641	. 2 |- ( ph -> A C_ U. J )
21		cnextucn.c	. . 3 |- ( ph -> ( ( cls ` J ) ` A ) = X )
22	21, 19	eqtrd 2656	. 2 |- ( ph -> ( ( cls ` J ) ` A ) = U. J )
23	10, 11	istps 20738	. . . . . 6 |- ( W e. TopSp <-> K e. (TopOn ` Y ) )
24	9, 23	sylib 208	. . . . 5 |- ( ph -> K e. (TopOn ` Y ) )
25	24	adantr 481	. . . 4 |- ( ( ph /\ x e. U. J ) -> K e. (TopOn ` Y ) )
26	19	eleq2d 2687	. . . . . . 7 |- ( ph -> ( x e. X <-> x e. U. J ) )
27	26	biimpar 502	. . . . . 6 |- ( ( ph /\ x e. U. J ) -> x e. X )
28	21	adantr 481	. . . . . 6 |- ( ( ph /\ x e. U. J ) -> ( ( cls ` J ) ` A ) = X )
29	27, 28	eleqtrrd 2704	. . . . 5 |- ( ( ph /\ x e. U. J ) -> x e. ( ( cls ` J ) ` A ) )
30	1	toptopon 20722	. . . . . . . . 9 |- ( J e. Top <-> J e. (TopOn ` U. J ) )
31	6, 30	sylib 208	. . . . . . . 8 |- ( ph -> J e. (TopOn ` U. J ) )
32		fveq2 6191	. . . . . . . . . 10 |- ( X = U. J -> (TopOn ` X ) = (TopOn ` U. J ) )
33	32	eleq2d 2687	. . . . . . . . 9 |- ( X = U. J -> ( J e. (TopOn ` X ) <-> J e. (TopOn ` U. J ) ) )
34	19, 33	syl 17	. . . . . . . 8 |- ( ph -> ( J e. (TopOn ` X ) <-> J e. (TopOn ` U. J ) ) )
35	31, 34	mpbird 247	. . . . . . 7 |- ( ph -> J e. (TopOn ` X ) )
36	35	adantr 481	. . . . . 6 |- ( ( ph /\ x e. U. J ) -> J e. (TopOn ` X ) )
37	16	adantr 481	. . . . . 6 |- ( ( ph /\ x e. U. J ) -> A C_ X )
38		trnei 21696	. . . . . 6 |- ( ( J e. (TopOn ` X ) /\ A C_ X /\ x e. X ) -> ( x e. ( ( cls ` J ) ` A ) <-> ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( Fil ` A ) ) )
39	36, 37, 27, 38	syl3anc 1326	. . . . 5 |- ( ( ph /\ x e. U. J ) -> ( x e. ( ( cls ` J ) ` A ) <-> ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( Fil ` A ) ) )
40	29, 39	mpbid 222	. . . 4 |- ( ( ph /\ x e. U. J ) -> ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( Fil ` A ) )
41	8	adantr 481	. . . 4 |- ( ( ph /\ x e. U. J ) -> F : A --> Y )
42		flfval 21794	. . . 4 |- ( ( K e. (TopOn ` Y ) /\ ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( Fil ` A ) /\ F : A --> Y ) -> ( ( K fLimf ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ` F ) = ( K fLim ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ) )
43	25, 40, 41, 42	syl3anc 1326	. . 3 |- ( ( ph /\ x e. U. J ) -> ( ( K fLimf ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ` F ) = ( K fLim ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ) )
44		cnextucn.w	. . . . 5 |- ( ph -> W e. CUnifSp )
45	44	adantr 481	. . . 4 |- ( ( ph /\ x e. U. J ) -> W e. CUnifSp )
46		cnextucn.l	. . . . . 6 |- ( ( ph /\ x e. X ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. (CauFilu ` U ) )
47	27, 46	syldan 487	. . . . 5 |- ( ( ph /\ x e. U. J ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. (CauFilu ` U ) )
48		cnextucn.u	. . . . . 6 |- U = (UnifSt ` W )
49	48	fveq2i 6194	. . . . 5 |- (CauFilu ` U ) = (CauFilu ` (UnifSt ` W ) )
50	47, 49	syl6eleq 2711	. . . 4 |- ( ( ph /\ x e. U. J ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. (CauFilu ` (UnifSt ` W ) ) )
51		fvex 6201	. . . . . . 7 |- ( Base ` W ) e. _V
52	10, 51	eqeltri 2697	. . . . . 6 |- Y e. _V
53	52	a1i 11	. . . . 5 |- ( ( ph /\ x e. U. J ) -> Y e. _V )
54		filfbas 21652	. . . . . 6 |- ( ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( Fil ` A ) -> ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( fBas ` A ) )
55	40, 54	syl 17	. . . . 5 |- ( ( ph /\ x e. U. J ) -> ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( fBas ` A ) )
56		fmfil 21748	. . . . 5 |- ( ( Y e. _V /\ ( ( ( nei ` J ) ` { x } ) ↾t A ) e. ( fBas ` A ) /\ F : A --> Y ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. ( Fil ` Y ) )
57	53, 55, 41, 56	syl3anc 1326	. . . 4 |- ( ( ph /\ x e. U. J ) -> ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. ( Fil ` Y ) )
58	10, 11	cuspcvg 22105	. . . 4 |- ( ( W e. CUnifSp /\ ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. (CauFilu ` (UnifSt ` W ) ) /\ ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) e. ( Fil ` Y ) ) -> ( K fLim ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ) =/= (/) )
59	45, 50, 57, 58	syl3anc 1326	. . 3 |- ( ( ph /\ x e. U. J ) -> ( K fLim ( ( Y FilMap F ) ` ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ) =/= (/) )
60	43, 59	eqnetrd 2861	. 2 |- ( ( ph /\ x e. U. J ) -> ( ( K fLimf ( ( ( nei ` J ) ` { x } ) ↾t A ) ) ` F ) =/= (/) )
61		cuspusp 22104	. . . 4 |- ( W e. CUnifSp -> W e. UnifSp )
62	44, 61	syl 17	. . 3 |- ( ph -> W e. UnifSp )
63	11	uspreg 22078	. . 3 |- ( ( W e. UnifSp /\ K e. Haus ) -> K e. Reg )
64	62, 7, 63	syl2anc 693	. 2 |- ( ph -> K e. Reg )
65	1, 2, 6, 7, 15, 20, 22, 60, 64	cnextcn 21871	1 |- ( ph -> ( ( JCnExt K ) ` F ) e. ( J Cn K ) )

Syntax hints:   -> wi 4   <-> wb 196   /\ wa 384   = wceq 1483   e. wcel 1990   =/= wne 2794   _Vcvv 3200   C_ wss 3574   (/)c0 3915   {csn 4177   U.cuni 4436   -->wf 5884   ` cfv 5888  (class class class)co 6650   Basecbs 15857   ↾_t crest 16081   TopOpenctopn 16082   fBascfbas 19734   Topctop 20698  TopOnctopon 20715   TopSpctps 20736   clsccl 20822   neicnei 20901   Cn ccn 21028   Hauscha 21112   Regcreg 21113   Filcfil 21649   FilMap cfm 21737   fLim cflim 21738   fLimf cflf 21739  CnExtccnext 21863  UnifStcuss 22057  UnifSpcusp 22058  CauFil_uccfilu 22090  CUnifSpccusp 22101

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-nel 2898  df-ral 2917  df-rex 2918  df-reu 2919  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-int 4476  df-iun 4522  df-iin 4523  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-oadd 7564  df-er 7742  df-map 7859  df-pm 7860  df-en 7956  df-fin 7959  df-fi 8317  df-rest 16083  df-topgen 16104  df-fbas 19743  df-fg 19744  df-top 20699  df-topon 20716  df-topsp 20737  df-bases 20750  df-cld 20823  df-ntr 20824  df-cls 20825  df-nei 20902  df-cn 21031  df-cnp 21032  df-haus 21119  df-reg 21120  df-tx 21365  df-fil 21650  df-fm 21742  df-flim 21743  df-flf 21744  df-cnext 21864  df-ust 22004  df-utop 22035  df-usp 22061  df-cusp 22102

This theorem is referenced by:  ucnextcn  22108