Theorem cnvssco 44796

Description: A condition weaker than reflexivity. (Contributed by RP, 3-Aug-2020.)

Assertion

Ref	Expression
cnvssco	⊢ (◡𝐴 ⊆ ◡(𝐵 ∘ 𝐶) ↔ ∀𝑥∀𝑦∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)))

Distinct variable groups:   𝑥,𝑦,𝑧,𝐴   𝑥,𝐵,𝑦,𝑧   𝑥,𝐶,𝑦,𝑧

Proof of Theorem cnvssco

Step	Hyp	Ref	Expression
1		alcom 2199	. 2 ⊢ (∀𝑦∀𝑥(⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)) ↔ ∀𝑥∀𝑦(⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)))
2		relcnv 6111	. . 3 ⊢ Rel ◡𝐴
3		ssrel 5764	. . 3 ⊢ (Rel ◡𝐴 → (◡𝐴 ⊆ ◡(𝐵 ∘ 𝐶) ↔ ∀𝑦∀𝑥(⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶))))
4	2, 3	ax-mp 5	. 2 ⊢ (◡𝐴 ⊆ ◡(𝐵 ∘ 𝐶) ↔ ∀𝑦∀𝑥(⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)))
5		19.37v 2032	. . . 4 ⊢ (∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)) ↔ (𝑥𝐴𝑦 → ∃𝑧(𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)))
6		vex 3458	. . . . . . 7 ⊢ 𝑦 ∈ V
7		vex 3458	. . . . . . 7 ⊢ 𝑥 ∈ V
8	6, 7	brcnv 5866	. . . . . 6 ⊢ (𝑦◡𝐴𝑥 ↔ 𝑥𝐴𝑦)
9		df-br 5107	. . . . . 6 ⊢ (𝑦◡𝐴𝑥 ↔ ⟨𝑦, 𝑥⟩ ∈ ◡𝐴)
10	8, 9	bitr3i 280	. . . . 5 ⊢ (𝑥𝐴𝑦 ↔ ⟨𝑦, 𝑥⟩ ∈ ◡𝐴)
11	7, 6	brco 5854	. . . . . 6 ⊢ (𝑥(𝐵 ∘ 𝐶)𝑦 ↔ ∃𝑧(𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦))
12	6, 7	brcnv 5866	. . . . . . 7 ⊢ (𝑦◡(𝐵 ∘ 𝐶)𝑥 ↔ 𝑥(𝐵 ∘ 𝐶)𝑦)
13		df-br 5107	. . . . . . 7 ⊢ (𝑦◡(𝐵 ∘ 𝐶)𝑥 ↔ ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶))
14	12, 13	bitr3i 280	. . . . . 6 ⊢ (𝑥(𝐵 ∘ 𝐶)𝑦 ↔ ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶))
15	11, 14	bitr3i 280	. . . . 5 ⊢ (∃𝑧(𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦) ↔ ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶))
16	10, 15	imbi12i 353	. . . 4 ⊢ ((𝑥𝐴𝑦 → ∃𝑧(𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)) ↔ (⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)))
17	5, 16	bitri 278	. . 3 ⊢ (∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)) ↔ (⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)))
18	17	2albii 1853	. 2 ⊢ (∀𝑥∀𝑦∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)) ↔ ∀𝑥∀𝑦(⟨𝑦, 𝑥⟩ ∈ ◡𝐴 → ⟨𝑦, 𝑥⟩ ∈ ◡(𝐵 ∘ 𝐶)))
19	1, 4, 18	3bitr4i 306	1 ⊢ (◡𝐴 ⊆ ◡(𝐵 ∘ 𝐶) ↔ ∀𝑥∀𝑦∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦)))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401  ∀wal 1568  ∃wex 1812   ∈ wcel 2147   ⊆ wss 3900  ⟨cop 4838   class class class wbr 5106  ^◡ccnv 5654   ∘ ccom 5659  Rel wrel 5660

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 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-11 2197  ax-ext 2735  ax-sep 5252  ax-pr 5395

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 2102  df-clab 2742  df-cleq 2755  df-clel 2839  df-rab 3417  df-v 3456  df-ss 3901  df-dif 4050  df-in 4094  df-un 4154  df-nul 4282  df-if 4486  df-sn 4589  df-pr 4591  df-op 4839  df-br 5107  df-opab 5171  df-xp 5661  df-rel 5662  df-cnv 5663  df-co 5664

This theorem is used by:  refimssco  44797