Theorem erthdmr 3221

Description: Basic property of equivalence relations. Compare Theorem 73 of [Suppes] p. 82. Assumes membership of the second argument in the domain.

Hypotheses

Ref	Expression
erthdmr.1	|- A e. V
erthdmr.2	|- B e. V
erthdmr.3	|- Er R

Assertion

Ref	Expression
erthdmr	|- (B e. dom R -> ([A]R = [B]R <-> ARB))

Proof of Theorem erthdmr

Step	Hyp	Ref	Expression
1		erthdmr.1	. . 3 |- A e. V
2		erthdmr.3	. . 3 |- Er R
3	1, 2	erthdm 3220	. 2 |- (B e. dom R -> ([B]R = [A]R <-> BRA))
4		cleqcom 1103	. 2 |- ([A]R = [B]R <-> [B]R = [A]R)
5		erthdmr.2	. . 3 |- B e. V
6	1, 5, 2	ersymb 3210	. 2 |- (ARB <-> BRA)
7	3, 4, 6	3bitr4g 428	1 |- (B e. dom R -> ([A]R = [B]R <-> ARB))

Syntax hints:   -> wi 2   <-> wb 127   = wceq 1091   e. wcel 1092  Vcvv 1348   class class class wbr 2054  dom cdm 2410  Er wer 3197  [cec 3198

This theorem is referenced by:  ereldm 3222

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-7 676  ax-gen 677  ax-8 798  ax-9 799  ax-10 800  ax-11 801  ax-12 802  ax-13 804  ax-14 805  ax-16 922  ax-17 925  ax-ext 1074  ax-rep 1075  ax-pow 1077

This theorem depends on definitions:  df-bi 128  df-or 197  df-an 198  df-3an 583  df-ex 679  df-sb 853  df-clab 1093  df-cleq 1097  df-clel 1099  df-rex 1206  df-v 1349  df-dif 1489  df-un 1490  df-in 1491  df-ss 1492  df-nul 1708  df-pw 1799  df-sn 1811  df-pr 1812  df-op 1815  df-br 2063  df-opab 2098  df-xp 2424  df-cnv 2426  df-co 2427  df-dm 2428  df-rn 2429  df-res 2430  df-ima 2431  df-er 3200  df-ec 3202

metamath.org