Theorem rn1st 45513

Description: The range of a function with a first-countable domain is itself first-countable. This is a variation of 1stcrestlem 23396, with a not-free hypothesis replacing a disjoint variable constraint. (Contributed by Glauco Siliprandi, 24-Jan-2025.)

Hypothesis

Ref	Expression
rn1st.1	⊢ Ⅎ𝑥𝐵

Assertion

Ref	Expression
rn1st	⊢ (𝐵 ≼ ω → ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω)

Proof of Theorem rn1st

Step	Hyp	Ref	Expression
1		ordom 7818	. . . . . 6 ⊢ Ord ω
2		reldom 8889	. . . . . . . 8 ⊢ Rel ≼
3	2	brrelex2i 5681	. . . . . . 7 ⊢ (𝐵 ≼ ω → ω ∈ V)
4		elong 6325	. . . . . . 7 ⊢ (ω ∈ V → (ω ∈ On ↔ Ord ω))
5	3, 4	syl 17	. . . . . 6 ⊢ (𝐵 ≼ ω → (ω ∈ On ↔ Ord ω))
6	1, 5	mpbiri 258	. . . . 5 ⊢ (𝐵 ≼ ω → ω ∈ On)
7		ondomen 9947	. . . . 5 ⊢ ((ω ∈ On ∧ 𝐵 ≼ ω) → 𝐵 ∈ dom card)
8	6, 7	mpancom 688	. . . 4 ⊢ (𝐵 ≼ ω → 𝐵 ∈ dom card)
9		rn1st.1	. . . . 5 ⊢ Ⅎ𝑥𝐵
10		eqid 2736	. . . . 5 ⊢ (𝑥 ∈ 𝐵 ↦ 𝐶) = (𝑥 ∈ 𝐵 ↦ 𝐶)
11	9, 10	dmmptssf 45472	. . . 4 ⊢ dom (𝑥 ∈ 𝐵 ↦ 𝐶) ⊆ 𝐵
12		ssnum 9949	. . . 4 ⊢ ((𝐵 ∈ dom card ∧ dom (𝑥 ∈ 𝐵 ↦ 𝐶) ⊆ 𝐵) → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ∈ dom card)
13	8, 11, 12	sylancl 586	. . 3 ⊢ (𝐵 ≼ ω → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ∈ dom card)
14		funmpt 6530	. . . 4 ⊢ Fun (𝑥 ∈ 𝐵 ↦ 𝐶)
15		funforn 6753	. . . 4 ⊢ (Fun (𝑥 ∈ 𝐵 ↦ 𝐶) ↔ (𝑥 ∈ 𝐵 ↦ 𝐶):dom (𝑥 ∈ 𝐵 ↦ 𝐶)–onto→ran (𝑥 ∈ 𝐵 ↦ 𝐶))
16	14, 15	mpbi 230	. . 3 ⊢ (𝑥 ∈ 𝐵 ↦ 𝐶):dom (𝑥 ∈ 𝐵 ↦ 𝐶)–onto→ran (𝑥 ∈ 𝐵 ↦ 𝐶)
17		fodomnum 9967	. . 3 ⊢ (dom (𝑥 ∈ 𝐵 ↦ 𝐶) ∈ dom card → ((𝑥 ∈ 𝐵 ↦ 𝐶):dom (𝑥 ∈ 𝐵 ↦ 𝐶)–onto→ran (𝑥 ∈ 𝐵 ↦ 𝐶) → ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ dom (𝑥 ∈ 𝐵 ↦ 𝐶)))
18	13, 16, 17	mpisyl 21	. 2 ⊢ (𝐵 ≼ ω → ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ dom (𝑥 ∈ 𝐵 ↦ 𝐶))
19		ctex 8900	. . . 4 ⊢ (𝐵 ≼ ω → 𝐵 ∈ V)
20		ssdomg 8937	. . . 4 ⊢ (𝐵 ∈ V → (dom (𝑥 ∈ 𝐵 ↦ 𝐶) ⊆ 𝐵 → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ 𝐵))
21	19, 11, 20	mpisyl 21	. . 3 ⊢ (𝐵 ≼ ω → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ 𝐵)
22		domtr 8944	. . 3 ⊢ ((dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ 𝐵 ∧ 𝐵 ≼ ω) → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω)
23	21, 22	mpancom 688	. 2 ⊢ (𝐵 ≼ ω → dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω)
24		domtr 8944	. 2 ⊢ ((ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ dom (𝑥 ∈ 𝐵 ↦ 𝐶) ∧ dom (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω) → ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω)
25	18, 23, 24	syl2anc 584	1 ⊢ (𝐵 ≼ ω → ran (𝑥 ∈ 𝐵 ↦ 𝐶) ≼ ω)

Syntax hints:   → wi 4   ↔ wb 206   ∈ wcel 2113  Ⅎwnfc 2883  Vcvv 3440   ⊆ wss 3901   class class class wbr 5098   ↦ cmpt 5179  dom cdm 5624  ran crn 5625  Ord word 6316  Oncon0 6317  Fun wfun 6486  –onto→wfo 6490  ωcom 7808   ≼ cdom 8881  cardccrd 9847

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2115  ax-9 2123  ax-10 2146  ax-11 2162  ax-12 2184  ax-ext 2708  ax-rep 5224  ax-sep 5241  ax-nul 5251  ax-pow 5310  ax-pr 5377  ax-un 7680

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1544  df-fal 1554  df-ex 1781  df-nf 1785  df-sb 2068  df-mo 2539  df-eu 2569  df-clab 2715  df-cleq 2728  df-clel 2811  df-nfc 2885  df-ne 2933  df-ral 3052  df-rex 3061  df-rmo 3350  df-reu 3351  df-rab 3400  df-v 3442  df-sbc 3741  df-csb 3850  df-dif 3904  df-un 3906  df-in 3908  df-ss 3918  df-pss 3921  df-nul 4286  df-if 4480  df-pw 4556  df-sn 4581  df-pr 4583  df-op 4587  df-uni 4864  df-int 4903  df-iun 4948  df-br 5099  df-opab 5161  df-mpt 5180  df-tr 5206  df-id 5519  df-eprel 5524  df-po 5532  df-so 5533  df-fr 5577  df-se 5578  df-we 5579  df-xp 5630  df-rel 5631  df-cnv 5632  df-co 5633  df-dm 5634  df-rn 5635  df-res 5636  df-ima 5637  df-pred 6259  df-ord 6320  df-on 6321  df-lim 6322  df-suc 6323  df-iota 6448  df-fun 6494  df-fn 6495  df-f 6496  df-f1 6497  df-fo 6498  df-f1o 6499  df-fv 6500  df-isom 6501  df-riota 7315  df-ov 7361  df-oprab 7362  df-mpo 7363  df-om 7809  df-1st 7933  df-2nd 7934  df-frecs 8223  df-wrecs 8254  df-recs 8303  df-er 8635  df-map 8765  df-en 8884  df-dom 8885  df-card 9851  df-acn 9854

This theorem is referenced by:  saliunclf  46562