Theorem mptfnf 6668

Description: The maps-to notation defines a function with domain. (Contributed by Scott Fenton, 21-Mar-2011.) (Revised by Thierry Arnoux, 10-May-2017.)

Hypothesis

Ref	Expression
mptfnf.0	⊢ Ⅎ𝑥𝐴

Assertion

Ref	Expression
mptfnf	⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ V ↔ (𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴)

Proof of Theorem mptfnf

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eueq 3680	. . 3 ⊢ (𝐵 ∈ V ↔ ∃!𝑦 𝑦 = 𝐵)
2	1	ralbii 3117	. 2 ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ V ↔ ∀𝑥 ∈ 𝐴 ∃!𝑦 𝑦 = 𝐵)
3		r19.26 3131	. . 3 ⊢ (∀𝑥 ∈ 𝐴 (∃𝑦 𝑦 = 𝐵 ∧ ∃*𝑦 𝑦 = 𝐵) ↔ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵))
4		df-eu 2603	. . . 4 ⊢ (∃!𝑦 𝑦 = 𝐵 ↔ (∃𝑦 𝑦 = 𝐵 ∧ ∃*𝑦 𝑦 = 𝐵))
5	4	ralbii 3117	. . 3 ⊢ (∀𝑥 ∈ 𝐴 ∃!𝑦 𝑦 = 𝐵 ↔ ∀𝑥 ∈ 𝐴 (∃𝑦 𝑦 = 𝐵 ∧ ∃*𝑦 𝑦 = 𝐵))
6		df-mpt 5194	. . . . . 6 ⊢ (𝑥 ∈ 𝐴 ↦ 𝐵) = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)}
7	6	fneq1i 6630	. . . . 5 ⊢ ((𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴 ↔ {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} Fn 𝐴)
8		df-fn 6537	. . . . 5 ⊢ ({⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} Fn 𝐴 ↔ (Fun {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} ∧ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = 𝐴))
9	7, 8	bitri 278	. . . 4 ⊢ ((𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴 ↔ (Fun {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} ∧ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = 𝐴))
10		moanimv 2653	. . . . . . 7 ⊢ (∃*𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵) ↔ (𝑥 ∈ 𝐴 → ∃*𝑦 𝑦 = 𝐵))
11	10	albii 1846	. . . . . 6 ⊢ (∀𝑥∃*𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∃*𝑦 𝑦 = 𝐵))
12		funopab 6569	. . . . . 6 ⊢ (Fun {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} ↔ ∀𝑥∃*𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵))
13		df-ral 3086	. . . . . 6 ⊢ (∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∃*𝑦 𝑦 = 𝐵))
14	11, 12, 13	3bitr4ri 307	. . . . 5 ⊢ (∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵 ↔ Fun {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)})
15		eqcom 2776	. . . . . 6 ⊢ ({𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)} = 𝐴 ↔ 𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)})
16		dmopab 5903	. . . . . . . 8 ⊢ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = {𝑥 ∣ ∃𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)}
17		19.42v 1980	. . . . . . . . 9 ⊢ (∃𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵) ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵))
18	17	abbii 2836	. . . . . . . 8 ⊢ {𝑥 ∣ ∃𝑦(𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)}
19	16, 18	eqtri 2792	. . . . . . 7 ⊢ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)}
20	19	eqeq1i 2774	. . . . . 6 ⊢ (dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = 𝐴 ↔ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)} = 𝐴)
21		pm4.71 566	. . . . . . . 8 ⊢ ((𝑥 ∈ 𝐴 → ∃𝑦 𝑦 = 𝐵) ↔ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)))
22	21	albii 1846	. . . . . . 7 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∃𝑦 𝑦 = 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)))
23		df-ral 3086	. . . . . . 7 ⊢ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∃𝑦 𝑦 = 𝐵))
24		mptfnf.0	. . . . . . . 8 ⊢ Ⅎ𝑥𝐴
25	24	eqabf 2960	. . . . . . 7 ⊢ (𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)} ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)))
26	22, 23, 25	3bitr4i 306	. . . . . 6 ⊢ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ↔ 𝐴 = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 = 𝐵)})
27	15, 20, 26	3bitr4ri 307	. . . . 5 ⊢ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ↔ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = 𝐴)
28	14, 27	anbi12i 639	. . . 4 ⊢ ((∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵) ↔ (Fun {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} ∧ dom {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵)} = 𝐴))
29		ancom 465	. . . 4 ⊢ ((∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵) ↔ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵))
30	9, 28, 29	3bitr2i 302	. . 3 ⊢ ((𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴 ↔ (∀𝑥 ∈ 𝐴 ∃𝑦 𝑦 = 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃*𝑦 𝑦 = 𝐵))
31	3, 5, 30	3bitr4ri 307	. 2 ⊢ ((𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴 ↔ ∀𝑥 ∈ 𝐴 ∃!𝑦 𝑦 = 𝐵)
32	2, 31	bitr4i 281	1 ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ V ↔ (𝑥 ∈ 𝐴 ↦ 𝐵) Fn 𝐴)

Syntax hints:   → wi 4   ↔ wb 209   ∧ wa 400  ∀wal 1565   = wceq 1567  ∃wex 1806   ∈ wcel 2149  ∃*wmo 2571  ∃!weu 2602  {cab 2747  Ⅎwnfc 2916  ∀wral 3085  Vcvv 3463  {copab 5174   ↦ cmpt 5193  dom cdm 5659  Fun wfun 6528   Fn wfn 6529

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-10 2182  ax-11 2198  ax-12 2219  ax-ext 2741  ax-sep 5258  ax-pr 5402

This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1570  df-fal 1580  df-ex 1807  df-nf 1811  df-sb 2098  df-mo 2573  df-eu 2603  df-clab 2748  df-cleq 2761  df-clel 2844  df-nfc 2918  df-ral 3086  df-rex 3096  df-rab 3424  df-v 3465  df-dif 3916  df-un 3918  df-in 3920  df-ss 3930  df-nul 4295  df-if 4490  df-sn 4592  df-pr 4594  df-op 4598  df-br 5111  df-opab 5175  df-mpt 5194  df-id 5554  df-xp 5665  df-rel 5666  df-cnv 5667  df-co 5668  df-dm 5669  df-fun 6536  df-fn 6537

This theorem is referenced by:  fnmptf  6669  mptfnd  45844  fnmptif  45867  nthrucw  47489  sinnpoly  47512