Theorem cnconn 22926

Description: Connectedness is respected by a continuous onto map. (Contributed by Jeff Hankins, 12-Jul-2009.) (Proof shortened by Mario Carneiro, 10-Mar-2015.)

Hypothesis

Ref	Expression
cnconn.2	⊢ 𝑌 = ∪ 𝐾

Assertion

Ref	Expression
cnconn	⊢ ((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) → 𝐾 ∈ Conn)

Proof of Theorem cnconn

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		cntop2 22745	. . 3 ⊢ (𝐹 ∈ (𝐽 Cn 𝐾) → 𝐾 ∈ Top)
2	1	3ad2ant3 1136	. 2 ⊢ ((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) → 𝐾 ∈ Top)
3		df-ne 2942	. . . . . . 7 ⊢ (𝑥 ≠ ∅ ↔ ¬ 𝑥 = ∅)
4		eqid 2733	. . . . . . . . . . . 12 ⊢ ∪ 𝐽 = ∪ 𝐽
5		simpl1 1192	. . . . . . . . . . . 12 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝐽 ∈ Conn)
6		simpl3 1194	. . . . . . . . . . . . 13 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝐹 ∈ (𝐽 Cn 𝐾))
7		simprl 770	. . . . . . . . . . . . . 14 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)))
8	7	elin1d 4199	. . . . . . . . . . . . 13 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ∈ 𝐾)
9		cnima 22769	. . . . . . . . . . . . 13 ⊢ ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝑥 ∈ 𝐾) → (◡𝐹 “ 𝑥) ∈ 𝐽)
10	6, 8, 9	syl2anc 585	. . . . . . . . . . . 12 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (◡𝐹 “ 𝑥) ∈ 𝐽)
11		elssuni 4942	. . . . . . . . . . . . . . . . . . 19 ⊢ (𝑥 ∈ 𝐾 → 𝑥 ⊆ ∪ 𝐾)
12	8, 11	syl 17	. . . . . . . . . . . . . . . . . 18 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ⊆ ∪ 𝐾)
13		cnconn.2	. . . . . . . . . . . . . . . . . 18 ⊢ 𝑌 = ∪ 𝐾
14	12, 13	sseqtrrdi 4034	. . . . . . . . . . . . . . . . 17 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ⊆ 𝑌)
15		simpl2 1193	. . . . . . . . . . . . . . . . . 18 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝐹:𝑋–onto→𝑌)
16		forn 6809	. . . . . . . . . . . . . . . . . 18 ⊢ (𝐹:𝑋–onto→𝑌 → ran 𝐹 = 𝑌)
17	15, 16	syl 17	. . . . . . . . . . . . . . . . 17 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → ran 𝐹 = 𝑌)
18	14, 17	sseqtrrd 4024	. . . . . . . . . . . . . . . 16 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ⊆ ran 𝐹)
19		df-rn 5688	. . . . . . . . . . . . . . . 16 ⊢ ran 𝐹 = dom ◡𝐹
20	18, 19	sseqtrdi 4033	. . . . . . . . . . . . . . 15 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ⊆ dom ◡𝐹)
21		sseqin2 4216	. . . . . . . . . . . . . . 15 ⊢ (𝑥 ⊆ dom ◡𝐹 ↔ (dom ◡𝐹 ∩ 𝑥) = 𝑥)
22	20, 21	sylib 217	. . . . . . . . . . . . . 14 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (dom ◡𝐹 ∩ 𝑥) = 𝑥)
23		simprr 772	. . . . . . . . . . . . . 14 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ≠ ∅)
24	22, 23	eqnetrd 3009	. . . . . . . . . . . . 13 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (dom ◡𝐹 ∩ 𝑥) ≠ ∅)
25		imadisj 6080	. . . . . . . . . . . . . 14 ⊢ ((◡𝐹 “ 𝑥) = ∅ ↔ (dom ◡𝐹 ∩ 𝑥) = ∅)
26	25	necon3bii 2994	. . . . . . . . . . . . 13 ⊢ ((◡𝐹 “ 𝑥) ≠ ∅ ↔ (dom ◡𝐹 ∩ 𝑥) ≠ ∅)
27	24, 26	sylibr 233	. . . . . . . . . . . 12 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (◡𝐹 “ 𝑥) ≠ ∅)
28	7	elin2d 4200	. . . . . . . . . . . . 13 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 ∈ (Clsd‘𝐾))
29		cnclima 22772	. . . . . . . . . . . . 13 ⊢ ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝑥 ∈ (Clsd‘𝐾)) → (◡𝐹 “ 𝑥) ∈ (Clsd‘𝐽))
30	6, 28, 29	syl2anc 585	. . . . . . . . . . . 12 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (◡𝐹 “ 𝑥) ∈ (Clsd‘𝐽))
31	4, 5, 10, 27, 30	connclo 22919	. . . . . . . . . . 11 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (◡𝐹 “ 𝑥) = ∪ 𝐽)
32	4, 13	cnf 22750	. . . . . . . . . . . 12 ⊢ (𝐹 ∈ (𝐽 Cn 𝐾) → 𝐹:∪ 𝐽⟶𝑌)
33		fdm 6727	. . . . . . . . . . . 12 ⊢ (𝐹:∪ 𝐽⟶𝑌 → dom 𝐹 = ∪ 𝐽)
34	6, 32, 33	3syl 18	. . . . . . . . . . 11 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → dom 𝐹 = ∪ 𝐽)
35		fof 6806	. . . . . . . . . . . 12 ⊢ (𝐹:𝑋–onto→𝑌 → 𝐹:𝑋⟶𝑌)
36		fdm 6727	. . . . . . . . . . . 12 ⊢ (𝐹:𝑋⟶𝑌 → dom 𝐹 = 𝑋)
37	15, 35, 36	3syl 18	. . . . . . . . . . 11 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → dom 𝐹 = 𝑋)
38	31, 34, 37	3eqtr2d 2779	. . . . . . . . . 10 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (◡𝐹 “ 𝑥) = 𝑋)
39	38	imaeq2d 6060	. . . . . . . . 9 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (𝐹 “ (◡𝐹 “ 𝑥)) = (𝐹 “ 𝑋))
40		foimacnv 6851	. . . . . . . . . 10 ⊢ ((𝐹:𝑋–onto→𝑌 ∧ 𝑥 ⊆ 𝑌) → (𝐹 “ (◡𝐹 “ 𝑥)) = 𝑥)
41	15, 14, 40	syl2anc 585	. . . . . . . . 9 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (𝐹 “ (◡𝐹 “ 𝑥)) = 𝑥)
42		foima 6811	. . . . . . . . . 10 ⊢ (𝐹:𝑋–onto→𝑌 → (𝐹 “ 𝑋) = 𝑌)
43	15, 42	syl 17	. . . . . . . . 9 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → (𝐹 “ 𝑋) = 𝑌)
44	39, 41, 43	3eqtr3d 2781	. . . . . . . 8 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) ∧ 𝑥 ≠ ∅)) → 𝑥 = 𝑌)
45	44	expr 458	. . . . . . 7 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ 𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾))) → (𝑥 ≠ ∅ → 𝑥 = 𝑌))
46	3, 45	biimtrrid 242	. . . . . 6 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ 𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾))) → (¬ 𝑥 = ∅ → 𝑥 = 𝑌))
47	46	orrd 862	. . . . 5 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ 𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾))) → (𝑥 = ∅ ∨ 𝑥 = 𝑌))
48		vex 3479	. . . . . 6 ⊢ 𝑥 ∈ V
49	48	elpr 4652	. . . . 5 ⊢ (𝑥 ∈ {∅, 𝑌} ↔ (𝑥 = ∅ ∨ 𝑥 = 𝑌))
50	47, 49	sylibr 233	. . . 4 ⊢ (((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) ∧ 𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾))) → 𝑥 ∈ {∅, 𝑌})
51	50	ex 414	. . 3 ⊢ ((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) → (𝑥 ∈ (𝐾 ∩ (Clsd‘𝐾)) → 𝑥 ∈ {∅, 𝑌}))
52	51	ssrdv 3989	. 2 ⊢ ((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) → (𝐾 ∩ (Clsd‘𝐾)) ⊆ {∅, 𝑌})
53	13	isconn2 22918	. 2 ⊢ (𝐾 ∈ Conn ↔ (𝐾 ∈ Top ∧ (𝐾 ∩ (Clsd‘𝐾)) ⊆ {∅, 𝑌}))
54	2, 52, 53	sylanbrc 584	1 ⊢ ((𝐽 ∈ Conn ∧ 𝐹:𝑋–onto→𝑌 ∧ 𝐹 ∈ (𝐽 Cn 𝐾)) → 𝐾 ∈ Conn)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 397   ∨ wo 846   ∧ w3a 1088   = wceq 1542   ∈ wcel 2107   ≠ wne 2941   ∩ cin 3948   ⊆ wss 3949  ∅c0 4323  {cpr 4631  ∪ cuni 4909  ^◡ccnv 5676  dom cdm 5677  ran crn 5678   “ cima 5680  ⟶wf 6540  –onto→wfo 6542  ‘cfv 6544  (class class class)co 7409  Topctop 22395  Clsdccld 22520   Cn ccn 22728  Conncconn 22915

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704  ax-sep 5300  ax-nul 5307  ax-pow 5364  ax-pr 5428  ax-un 7725

This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ne 2942  df-ral 3063  df-rex 3072  df-rab 3434  df-v 3477  df-sbc 3779  df-dif 3952  df-un 3954  df-in 3956  df-ss 3966  df-nul 4324  df-if 4530  df-pw 4605  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4910  df-br 5150  df-opab 5212  df-mpt 5233  df-id 5575  df-xp 5683  df-rel 5684  df-cnv 5685  df-co 5686  df-dm 5687  df-rn 5688  df-res 5689  df-ima 5690  df-iota 6496  df-fun 6546  df-fn 6547  df-f 6548  df-fo 6550  df-fv 6552  df-ov 7412  df-oprab 7413  df-mpo 7414  df-map 8822  df-top 22396  df-topon 22413  df-cld 22523  df-cn 22731  df-conn 22916

This theorem is referenced by:  connima  22929  conncn  22930  qtopconn  23213  connhmph  23293  ivthALT  35220