Theorem fxpval 33516

Description: Value of the set of fixed points. (Contributed by Thierry Arnoux, 18-Nov-2025.)

Hypotheses

Ref	Expression
fxpval.1	⊢ (𝜑 → 𝐵 ∈ 𝑉)
fxpval.2	⊢ (𝜑 → 𝐴 ∈ 𝑊)

Assertion

Ref	Expression
fxpval	⊢ (𝜑 → (𝐵FixPts𝐴) = {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥})

Distinct variable groups:   𝐴,𝑝,𝑥   𝑥,𝐵

Allowed substitution hints:   𝜑(𝑥, 𝑝)   𝐵(𝑝)   𝑉(𝑥, 𝑝)   𝑊(𝑥, 𝑝)

Proof of Theorem fxpval

Dummy variables 𝑎 𝑏 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-fxp 33515	. . 3 ⊢ FixPts = (𝑏 ∈ V, 𝑎 ∈ V ↦ {𝑥 ∈ 𝑏 ∣ ∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥})
2	1	a1i 11	. 2 ⊢ (𝜑 → FixPts = (𝑏 ∈ V, 𝑎 ∈ V ↦ {𝑥 ∈ 𝑏 ∣ ∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥}))
3		simpl 488	. . . 4 ⊢ ((𝑏 = 𝐵 ∧ 𝑎 = 𝐴) → 𝑏 = 𝐵)
4		dmeq 5898	. . . . . . 7 ⊢ (𝑎 = 𝐴 → dom 𝑎 = dom 𝐴)
5	4	dmeqd 5900	. . . . . 6 ⊢ (𝑎 = 𝐴 → dom dom 𝑎 = dom dom 𝐴)
6		oveq 7429	. . . . . . 7 ⊢ (𝑎 = 𝐴 → (𝑝𝑎𝑥) = (𝑝𝐴𝑥))
7	6	eqeq1d 2768	. . . . . 6 ⊢ (𝑎 = 𝐴 → ((𝑝𝑎𝑥) = 𝑥 ↔ (𝑝𝐴𝑥) = 𝑥))
8	5, 7	raleqbidv 3341	. . . . 5 ⊢ (𝑎 = 𝐴 → (∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥 ↔ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥))
9	8	adantl 487	. . . 4 ⊢ ((𝑏 = 𝐵 ∧ 𝑎 = 𝐴) → (∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥 ↔ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥))
10	3, 9	rabeqbidv 3437	. . 3 ⊢ ((𝑏 = 𝐵 ∧ 𝑎 = 𝐴) → {𝑥 ∈ 𝑏 ∣ ∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥} = {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥})
11	10	adantl 487	. 2 ⊢ ((𝜑 ∧ (𝑏 = 𝐵 ∧ 𝑎 = 𝐴)) → {𝑥 ∈ 𝑏 ∣ ∀𝑝 ∈ dom dom 𝑎(𝑝𝑎𝑥) = 𝑥} = {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥})
12		fxpval.1	. . 3 ⊢ (𝜑 → 𝐵 ∈ 𝑉)
13	12	elexd 3481	. 2 ⊢ (𝜑 → 𝐵 ∈ V)
14		fxpval.2	. . 3 ⊢ (𝜑 → 𝐴 ∈ 𝑊)
15	14	elexd 3481	. 2 ⊢ (𝜑 → 𝐴 ∈ V)
16		eqid 2766	. . 3 ⊢ {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥} = {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥}
17	16, 12	rabexd 5315	. 2 ⊢ (𝜑 → {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥} ∈ V)
18	2, 11, 13, 15, 17	ovmpod 7575	1 ⊢ (𝜑 → (𝐵FixPts𝐴) = {𝑥 ∈ 𝐵 ∣ ∀𝑝 ∈ dom dom 𝐴(𝑝𝐴𝑥) = 𝑥})

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1570   ∈ wcel 2146  ∀wral 3082  {crab 3419  Vcvv 3458  dom cdm 5666  (class class class)co 7423   ∈ cmpo 7425  FixPtscfxp 33514

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-10 2179  ax-11 2195  ax-12 2216  ax-ext 2738  ax-sep 5262  ax-pr 5409

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2570  df-eu 2600  df-clab 2745  df-cleq 2758  df-clel 2841  df-nfc 2915  df-ral 3083  df-rex 3093  df-rab 3420  df-v 3460  df-sbc 3748  df-dif 3911  df-un 3913  df-in 3915  df-ss 3925  df-nul 4290  df-if 4493  df-pw 4569  df-sn 4595  df-pr 4597  df-op 4601  df-uni 4878  df-br 5115  df-opab 5179  df-id 5561  df-xp 5672  df-rel 5673  df-cnv 5674  df-co 5675  df-dm 5676  df-iota 6499  df-fun 6545  df-fv 6551  df-ov 7426  df-oprab 7427  df-mpo 7428  df-fxp 33515

This theorem is used by:  fxpss  33517  fxpgaval  33518