Theorem erref 8046

Description: An equivalence relation is reflexive on its field. Compare Theorem 3M of [Enderton] p. 56. (Contributed by Mario Carneiro, 6-May-2013.) (Revised by Mario Carneiro, 12-Aug-2015.)

Hypotheses

Ref	Expression
ersymb.1	⊢ (𝜑 → 𝑅 Er 𝑋)
erref.2	⊢ (𝜑 → 𝐴 ∈ 𝑋)

Assertion

Ref	Expression
erref	⊢ (𝜑 → 𝐴𝑅𝐴)

Proof of Theorem erref

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		erref.2	. . . 4 ⊢ (𝜑 → 𝐴 ∈ 𝑋)
2		ersymb.1	. . . . 5 ⊢ (𝜑 → 𝑅 Er 𝑋)
3		erdm 8036	. . . . 5 ⊢ (𝑅 Er 𝑋 → dom 𝑅 = 𝑋)
4	2, 3	syl 17	. . . 4 ⊢ (𝜑 → dom 𝑅 = 𝑋)
5	1, 4	eleqtrrd 2861	. . 3 ⊢ (𝜑 → 𝐴 ∈ dom 𝑅)
6		eldmg 5564	. . . 4 ⊢ (𝐴 ∈ 𝑋 → (𝐴 ∈ dom 𝑅 ↔ ∃𝑥 𝐴𝑅𝑥))
7	1, 6	syl 17	. . 3 ⊢ (𝜑 → (𝐴 ∈ dom 𝑅 ↔ ∃𝑥 𝐴𝑅𝑥))
8	5, 7	mpbid 224	. 2 ⊢ (𝜑 → ∃𝑥 𝐴𝑅𝑥)
9	2	adantr 474	. . 3 ⊢ ((𝜑 ∧ 𝐴𝑅𝑥) → 𝑅 Er 𝑋)
10		simpr 479	. . 3 ⊢ ((𝜑 ∧ 𝐴𝑅𝑥) → 𝐴𝑅𝑥)
11	9, 10, 10	ertr4d 8045	. 2 ⊢ ((𝜑 ∧ 𝐴𝑅𝑥) → 𝐴𝑅𝐴)
12	8, 11	exlimddv 1978	1 ⊢ (𝜑 → 𝐴𝑅𝐴)

Syntax hints:   → wi 4   ↔ wb 198   ∧ wa 386   = wceq 1601  ∃wex 1823   ∈ wcel 2106   class class class wbr 4886  dom cdm 5355   Er wer 8023

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1839  ax-4 1853  ax-5 1953  ax-6 2021  ax-7 2054  ax-9 2115  ax-10 2134  ax-11 2149  ax-12 2162  ax-13 2333  ax-ext 2753  ax-sep 5017  ax-nul 5025  ax-pr 5138

This theorem depends on definitions:  df-bi 199  df-an 387  df-or 837  df-3an 1073  df-tru 1605  df-ex 1824  df-nf 1828  df-sb 2012  df-mo 2550  df-eu 2586  df-clab 2763  df-cleq 2769  df-clel 2773  df-nfc 2920  df-ral 3094  df-rex 3095  df-rab 3098  df-v 3399  df-dif 3794  df-un 3796  df-in 3798  df-ss 3805  df-nul 4141  df-if 4307  df-sn 4398  df-pr 4400  df-op 4404  df-br 4887  df-opab 4949  df-xp 5361  df-rel 5362  df-cnv 5363  df-co 5364  df-dm 5365  df-er 8026

This theorem is referenced by:  iserd  8052  erth  8073  iiner  8102  erinxp  8104  nqerid  10090  enqeq  10091  qusgrp  18033  sylow2alem1  18416  sylow2alem2  18417  sylow2a  18418  efginvrel2  18524  efgsrel  18531  efgcpbllemb  18554  frgp0  18559  frgpnabllem1  18662  frgpnabllem2  18663  pcophtb  23236  pi1xfrf  23260  pi1xfr  23262  pi1xfrcnvlem  23263  prtlem10  35013