Theorem ecid 8784

Description: A set is equal to its coset under the converse membership relation. (Note: the converse membership relation is not an equivalence relation.) (Contributed by NM, 13-Aug-1995.) (Revised by Mario Carneiro, 9-Jul-2014.)

Hypothesis

Ref	Expression
ecid.1	⊢ 𝐴 ∈ V

Assertion

Ref	Expression
ecid	⊢ [𝐴]◡ E = 𝐴

Proof of Theorem ecid

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		vex 3457	. . . 4 ⊢ 𝑦 ∈ V
2		ecid.1	. . . 4 ⊢ 𝐴 ∈ V
3	1, 2	elec 8747	. . 3 ⊢ (𝑦 ∈ [𝐴]◡ E ↔ 𝐴◡ E 𝑦)
4	2, 1	brcnv 5866	. . 3 ⊢ (𝐴◡ E 𝑦 ↔ 𝑦 E 𝐴)
5	2	epeli 5561	. . 3 ⊢ (𝑦 E 𝐴 ↔ 𝑦 ∈ 𝐴)
6	3, 4, 5	3bitri 300	. 2 ⊢ (𝑦 ∈ [𝐴]◡ E ↔ 𝑦 ∈ 𝐴)
7	6	eqriv 2759	1 ⊢ [𝐴]◡ E = 𝐴

This proof depends on syntax axioms:   = wceq 1570   ∈ wcel 2145  Vcvv 3453   class class class wbr 5107   E cep 5558  ^◡ccnv 5658  [cec 8698

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 2147  ax-9 2155  ax-ext 2734  ax-sep 5255  ax-pr 5402

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-sb 2100  df-clab 2741  df-cleq 2754  df-clel 2837  df-ne 2958  df-ral 3079  df-rex 3089  df-rab 3415  df-v 3455  df-dif 3905  df-un 3907  df-in 3909  df-ss 3919  df-nul 4283  df-if 4486  df-sn 4588  df-pr 4590  df-op 4594  df-br 5108  df-opab 5172  df-eprel 5559  df-xp 5665  df-cnv 5667  df-dm 5669  df-rn 5670  df-res 5671  df-ima 5672  df-ec 8702

This theorem is used by:  qsid  8785  addcnsrec  11156  mulcnsrec  11157