Theorem rn1st 45274

Description: The range of a function with a first-countable domain is itself first-countable. This is a variation of 1stcrestlem 23346, 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 7855	. . . . . 6 ⊢ Ord ω
2		reldom 8927	. . . . . . . 8 ⊢ Rel ≼
3	2	brrelex2i 5698	. . . . . . 7 ⊢ (𝐵 ≼ ω → ω ∈ V)
4		elong 6343	. . . . . . 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 9997	. . . . 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 2730	. . . . 5 ⊢ (𝑥 ∈ 𝐵 ↦ 𝐶) = (𝑥 ∈ 𝐵 ↦ 𝐶)
11	9, 10	dmmptssf 45233	. . . 4 ⊢ dom (𝑥 ∈ 𝐵 ↦ 𝐶) ⊆ 𝐵
12		ssnum 9999	. . . 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 6557	. . . 4 ⊢ Fun (𝑥 ∈ 𝐵 ↦ 𝐶)
15		funforn 6782	. . . 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 10017	. . 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 8938	. . . 4 ⊢ (𝐵 ≼ ω → 𝐵 ∈ V)
20		ssdomg 8974	. . . 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 8981	. . 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 8981	. 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 2109  Ⅎwnfc 2877  Vcvv 3450   ⊆ wss 3917   class class class wbr 5110   ↦ cmpt 5191  dom cdm 5641  ran crn 5642  Ord word 6334  Oncon0 6335  Fun wfun 6508  –onto→wfo 6512  ωcom 7845   ≼ cdom 8919  cardccrd 9895

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-10 2142  ax-11 2158  ax-12 2178  ax-ext 2702  ax-rep 5237  ax-sep 5254  ax-nul 5264  ax-pow 5323  ax-pr 5390  ax-un 7714

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2066  df-mo 2534  df-eu 2563  df-clab 2709  df-cleq 2722  df-clel 2804  df-nfc 2879  df-ne 2927  df-ral 3046  df-rex 3055  df-rmo 3356  df-reu 3357  df-rab 3409  df-v 3452  df-sbc 3757  df-csb 3866  df-dif 3920  df-un 3922  df-in 3924  df-ss 3934  df-pss 3937  df-nul 4300  df-if 4492  df-pw 4568  df-sn 4593  df-pr 4595  df-op 4599  df-uni 4875  df-int 4914  df-iun 4960  df-br 5111  df-opab 5173  df-mpt 5192  df-tr 5218  df-id 5536  df-eprel 5541  df-po 5549  df-so 5550  df-fr 5594  df-se 5595  df-we 5596  df-xp 5647  df-rel 5648  df-cnv 5649  df-co 5650  df-dm 5651  df-rn 5652  df-res 5653  df-ima 5654  df-pred 6277  df-ord 6338  df-on 6339  df-lim 6340  df-suc 6341  df-iota 6467  df-fun 6516  df-fn 6517  df-f 6518  df-f1 6519  df-fo 6520  df-f1o 6521  df-fv 6522  df-isom 6523  df-riota 7347  df-ov 7393  df-oprab 7394  df-mpo 7395  df-om 7846  df-1st 7971  df-2nd 7972  df-frecs 8263  df-wrecs 8294  df-recs 8343  df-er 8674  df-map 8804  df-en 8922  df-dom 8923  df-card 9899  df-acn 9902

This theorem is referenced by:  saliunclf  46327