Theorem br1cossinidres 38451

Description: 𝐵 and 𝐶 are cosets by an intersection with the restricted identity class: a binary relation. (Contributed by Peter Mazsa, 31-Dec-2021.)

Assertion

Ref	Expression
br1cossinidres	⊢ ((𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑊) → (𝐵 ≀ (𝑅 ∩ ( I ↾ 𝐴))𝐶 ↔ ∃𝑢 ∈ 𝐴 ((𝑢 = 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 = 𝐶 ∧ 𝑢𝑅𝐶))))

Distinct variable groups:   𝑢,𝐴   𝑢,𝐵   𝑢,𝐶   𝑢,𝑅   𝑢,𝑉   𝑢,𝑊

Proof of Theorem br1cossinidres

Step	Hyp	Ref	Expression
1		br1cossinres 38449	. 2 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑊) → (𝐵 ≀ (𝑅 ∩ ( I ↾ 𝐴))𝐶 ↔ ∃𝑢 ∈ 𝐴 ((𝑢 I 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 I 𝐶 ∧ 𝑢𝑅𝐶))))
2		ideq2 38309	. . . . . 6 ⊢ (𝑢 ∈ V → (𝑢 I 𝐵 ↔ 𝑢 = 𝐵))
3	2	elv 3484	. . . . 5 ⊢ (𝑢 I 𝐵 ↔ 𝑢 = 𝐵)
4	3	anbi1i 624	. . . 4 ⊢ ((𝑢 I 𝐵 ∧ 𝑢𝑅𝐵) ↔ (𝑢 = 𝐵 ∧ 𝑢𝑅𝐵))
5		ideq2 38309	. . . . . 6 ⊢ (𝑢 ∈ V → (𝑢 I 𝐶 ↔ 𝑢 = 𝐶))
6	5	elv 3484	. . . . 5 ⊢ (𝑢 I 𝐶 ↔ 𝑢 = 𝐶)
7	6	anbi1i 624	. . . 4 ⊢ ((𝑢 I 𝐶 ∧ 𝑢𝑅𝐶) ↔ (𝑢 = 𝐶 ∧ 𝑢𝑅𝐶))
8	4, 7	anbi12i 628	. . 3 ⊢ (((𝑢 I 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 I 𝐶 ∧ 𝑢𝑅𝐶)) ↔ ((𝑢 = 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 = 𝐶 ∧ 𝑢𝑅𝐶)))
9	8	rexbii 3093	. 2 ⊢ (∃𝑢 ∈ 𝐴 ((𝑢 I 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 I 𝐶 ∧ 𝑢𝑅𝐶)) ↔ ∃𝑢 ∈ 𝐴 ((𝑢 = 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 = 𝐶 ∧ 𝑢𝑅𝐶)))
10	1, 9	bitrdi 287	1 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑊) → (𝐵 ≀ (𝑅 ∩ ( I ↾ 𝐴))𝐶 ↔ ∃𝑢 ∈ 𝐴 ((𝑢 = 𝐵 ∧ 𝑢𝑅𝐵) ∧ (𝑢 = 𝐶 ∧ 𝑢𝑅𝐶))))

Syntax hints:   → wi 4   ↔ wb 206   ∧ wa 395   = wceq 1539   ∈ wcel 2107  ∃wrex 3069  Vcvv 3479   ∩ cin 3949   class class class wbr 5142   I cid 5576   ↾ cres 5686   ≀ ccoss 38183

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1794  ax-4 1808  ax-5 1909  ax-6 1966  ax-7 2006  ax-8 2109  ax-9 2117  ax-ext 2707  ax-sep 5295  ax-nul 5305  ax-pr 5431

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1779  df-sb 2064  df-clab 2714  df-cleq 2728  df-clel 2815  df-ral 3061  df-rex 3070  df-rab 3436  df-v 3481  df-dif 3953  df-un 3955  df-in 3957  df-ss 3967  df-nul 4333  df-if 4525  df-sn 4626  df-pr 4628  df-op 4632  df-br 5143  df-opab 5205  df-id 5577  df-xp 5690  df-rel 5691  df-cnv 5692  df-res 5696  df-coss 38413

This theorem is referenced by: (None)