Theorem extid 38998

Description: Property of identity relation, see also extep 38971, extssr 39271 and the comment of df-ssr 39260. (Contributed by Peter Mazsa, 5-Jul-2019.)

Assertion

Ref	Expression
extid	⊢ (𝐴 ∈ 𝑉 → ([𝐴]◡ I = [𝐵]◡ I ↔ 𝐴 = 𝐵))

Proof of Theorem extid

Step	Hyp	Ref	Expression
1		cnvi 5873	. . . . 5 ⊢ ◡ I = I
2	1	eceq2i 8739	. . . 4 ⊢ [𝐴]◡ I = [𝐴] I
3		ecidsn 8755	. . . 4 ⊢ [𝐴] I = {𝐴}
4	2, 3	eqtri 2788	. . 3 ⊢ [𝐴]◡ I = {𝐴}
5	1	eceq2i 8739	. . . 4 ⊢ [𝐵]◡ I = [𝐵] I
6		ecidsn 8755	. . . 4 ⊢ [𝐵] I = {𝐵}
7	5, 6	eqtri 2788	. . 3 ⊢ [𝐵]◡ I = {𝐵}
8	4, 7	eqeq12i 2783	. 2 ⊢ ([𝐴]◡ I = [𝐵]◡ I ↔ {𝐴} = {𝐵})
9		sneqbg 4810	. 2 ⊢ (𝐴 ∈ 𝑉 → ({𝐴} = {𝐵} ↔ 𝐴 = 𝐵))
10	8, 9	bitrid 286	1 ⊢ (𝐴 ∈ 𝑉 → ([𝐴]◡ I = [𝐵]◡ I ↔ 𝐴 = 𝐵))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   = wceq 1570   ∈ wcel 2146  {csn 4591   I cid 5557  ^◡ccnv 5662  [cec 8694

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-ext 2737  ax-sep 5259  ax-pr 5406

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 2744  df-cleq 2757  df-clel 2840  df-ral 3082  df-rex 3092  df-rab 3419  df-v 3459  df-dif 3909  df-un 3911  df-in 3913  df-ss 3923  df-nul 4287  df-if 4490  df-sn 4592  df-pr 4594  df-op 4598  df-br 5112  df-opab 5176  df-id 5558  df-xp 5669  df-rel 5670  df-cnv 5671  df-dm 5673  df-rn 5674  df-res 5675  df-ima 5676  df-ec 8698

This theorem is used by: (None)