Theorem brcodir 5515

Description: Two ways of saying that two elements have an upper bound. (Contributed by Mario Carneiro, 3-Nov-2015.)

Assertion

Ref	Expression
brcodir	⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴(◡𝑅 ∘ 𝑅)𝐵 ↔ ∃𝑧(𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧)))

Distinct variable groups:   𝑧,𝐴   𝑧,𝐵   𝑧,𝑅   𝑧,𝑉   𝑧,𝑊

Proof of Theorem brcodir

Step	Hyp	Ref	Expression
1		brcog 5288	. 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴(◡𝑅 ∘ 𝑅)𝐵 ↔ ∃𝑧(𝐴𝑅𝑧 ∧ 𝑧◡𝑅𝐵)))
2		vex 3203	. . . . . 6 ⊢ 𝑧 ∈ V
3		brcnvg 5303	. . . . . 6 ⊢ ((𝑧 ∈ V ∧ 𝐵 ∈ 𝑊) → (𝑧◡𝑅𝐵 ↔ 𝐵𝑅𝑧))
4	2, 3	mpan 706	. . . . 5 ⊢ (𝐵 ∈ 𝑊 → (𝑧◡𝑅𝐵 ↔ 𝐵𝑅𝑧))
5	4	anbi2d 740	. . . 4 ⊢ (𝐵 ∈ 𝑊 → ((𝐴𝑅𝑧 ∧ 𝑧◡𝑅𝐵) ↔ (𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧)))
6	5	adantl 482	. . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ((𝐴𝑅𝑧 ∧ 𝑧◡𝑅𝐵) ↔ (𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧)))
7	6	exbidv 1850	. 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (∃𝑧(𝐴𝑅𝑧 ∧ 𝑧◡𝑅𝐵) ↔ ∃𝑧(𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧)))
8	1, 7	bitrd 268	1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴(◡𝑅 ∘ 𝑅)𝐵 ↔ ∃𝑧(𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧)))

Syntax hints:   → wi 4   ↔ wb 196   ∧ wa 384  ∃wex 1704   ∈ wcel 1990  Vcvv 3200   class class class wbr 4653  ^◡ccnv 5113   ∘ ccom 5118

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pr 4906

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-rab 2921  df-v 3202  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-sn 4178  df-pr 4180  df-op 4184  df-br 4654  df-opab 4713  df-cnv 5122  df-co 5123

This theorem is referenced by:  codir  5516