Theorem cnss2 23301

Description: If the topology 𝐾 is finer than 𝐽, then there are fewer continuous functions into 𝐾 than into 𝐽 from some other space. (Contributed by Mario Carneiro, 19-Mar-2015.) (Revised by Mario Carneiro, 21-Aug-2015.)

Hypothesis

Ref	Expression
cnss2.1	⊢ 𝑌 = ∪ 𝐾

Assertion

Ref	Expression
cnss2	⊢ ((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) → (𝐽 Cn 𝐾) ⊆ (𝐽 Cn 𝐿))

Proof of Theorem cnss2

Dummy variables 𝑥 𝑓 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		eqid 2735	. . . . . 6 ⊢ ∪ 𝐽 = ∪ 𝐽
2		cnss2.1	. . . . . 6 ⊢ 𝑌 = ∪ 𝐾
3	1, 2	cnf 23270	. . . . 5 ⊢ (𝑓 ∈ (𝐽 Cn 𝐾) → 𝑓:∪ 𝐽⟶𝑌)
4	3	adantl 481	. . . 4 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝑓:∪ 𝐽⟶𝑌)
5		simplr 769	. . . . 5 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐿 ⊆ 𝐾)
6		cnima 23289	. . . . . . 7 ⊢ ((𝑓 ∈ (𝐽 Cn 𝐾) ∧ 𝑥 ∈ 𝐾) → (◡𝑓 “ 𝑥) ∈ 𝐽)
7	6	ralrimiva 3144	. . . . . 6 ⊢ (𝑓 ∈ (𝐽 Cn 𝐾) → ∀𝑥 ∈ 𝐾 (◡𝑓 “ 𝑥) ∈ 𝐽)
8	7	adantl 481	. . . . 5 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → ∀𝑥 ∈ 𝐾 (◡𝑓 “ 𝑥) ∈ 𝐽)
9		ssralv 4064	. . . . 5 ⊢ (𝐿 ⊆ 𝐾 → (∀𝑥 ∈ 𝐾 (◡𝑓 “ 𝑥) ∈ 𝐽 → ∀𝑥 ∈ 𝐿 (◡𝑓 “ 𝑥) ∈ 𝐽))
10	5, 8, 9	sylc 65	. . . 4 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → ∀𝑥 ∈ 𝐿 (◡𝑓 “ 𝑥) ∈ 𝐽)
11		cntop1 23264	. . . . . . 7 ⊢ (𝑓 ∈ (𝐽 Cn 𝐾) → 𝐽 ∈ Top)
12	11	adantl 481	. . . . . 6 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐽 ∈ Top)
13		toptopon2 22940	. . . . . 6 ⊢ (𝐽 ∈ Top ↔ 𝐽 ∈ (TopOn‘∪ 𝐽))
14	12, 13	sylib 218	. . . . 5 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐽 ∈ (TopOn‘∪ 𝐽))
15		simpll 767	. . . . 5 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐿 ∈ (TopOn‘𝑌))
16		iscn 23259	. . . . 5 ⊢ ((𝐽 ∈ (TopOn‘∪ 𝐽) ∧ 𝐿 ∈ (TopOn‘𝑌)) → (𝑓 ∈ (𝐽 Cn 𝐿) ↔ (𝑓:∪ 𝐽⟶𝑌 ∧ ∀𝑥 ∈ 𝐿 (◡𝑓 “ 𝑥) ∈ 𝐽)))
17	14, 15, 16	syl2anc 584	. . . 4 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → (𝑓 ∈ (𝐽 Cn 𝐿) ↔ (𝑓:∪ 𝐽⟶𝑌 ∧ ∀𝑥 ∈ 𝐿 (◡𝑓 “ 𝑥) ∈ 𝐽)))
18	4, 10, 17	mpbir2and 713	. . 3 ⊢ (((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) ∧ 𝑓 ∈ (𝐽 Cn 𝐾)) → 𝑓 ∈ (𝐽 Cn 𝐿))
19	18	ex 412	. 2 ⊢ ((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) → (𝑓 ∈ (𝐽 Cn 𝐾) → 𝑓 ∈ (𝐽 Cn 𝐿)))
20	19	ssrdv 4001	1 ⊢ ((𝐿 ∈ (TopOn‘𝑌) ∧ 𝐿 ⊆ 𝐾) → (𝐽 Cn 𝐾) ⊆ (𝐽 Cn 𝐿))

Syntax hints:   → wi 4   ↔ wb 206   ∧ wa 395   = wceq 1537   ∈ wcel 2106  ∀wral 3059   ⊆ wss 3963  ∪ cuni 4912  ^◡ccnv 5688   “ cima 5692  ⟶wf 6559  ‘cfv 6563  (class class class)co 7431  Topctop 22915  TopOnctopon 22932   Cn ccn 23248

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pow 5371  ax-pr 5438  ax-un 7754

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-rab 3434  df-v 3480  df-sbc 3792  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-pw 4607  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5583  df-xp 5695  df-rel 5696  df-cnv 5697  df-co 5698  df-dm 5699  df-rn 5700  df-res 5701  df-ima 5702  df-iota 6516  df-fun 6565  df-fn 6566  df-f 6567  df-fv 6571  df-ov 7434  df-oprab 7435  df-mpo 7436  df-map 8867  df-top 22916  df-topon 22933  df-cn 23251

This theorem is referenced by:  kgencn3  23582  xmetdcn  24874