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| Mirrors > Home > MPE Home > Th. List > Mathboxes > elrelscnveq2 | Structured version Visualization version GIF version | ||
| Description: Two ways of saying a relation is symmetric. (Contributed by Peter Mazsa, 22-Aug-2021.) | 
| Ref | Expression | 
|---|---|
| elrelscnveq2 | ⊢ (𝑅 ∈ Rels → (◡𝑅 = 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥))) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cnvsym 6132 | . . . 4 ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) | |
| 2 | 1 | a1i 11 | . . 3 ⊢ (𝑅 ∈ Rels → (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥))) | 
| 3 | elrelsrelim 38489 | . . . . . . 7 ⊢ (𝑅 ∈ Rels → Rel 𝑅) | |
| 4 | dfrel2 6209 | . . . . . . 7 ⊢ (Rel 𝑅 ↔ ◡◡𝑅 = 𝑅) | |
| 5 | 3, 4 | sylib 218 | . . . . . 6 ⊢ (𝑅 ∈ Rels → ◡◡𝑅 = 𝑅) | 
| 6 | 5 | sseq1d 4015 | . . . . 5 ⊢ (𝑅 ∈ Rels → (◡◡𝑅 ⊆ ◡𝑅 ↔ 𝑅 ⊆ ◡𝑅)) | 
| 7 | cnvsym 6132 | . . . . 5 ⊢ (◡◡𝑅 ⊆ ◡𝑅 ↔ ∀𝑥∀𝑦(𝑥◡𝑅𝑦 → 𝑦◡𝑅𝑥)) | |
| 8 | 6, 7 | bitr3di 286 | . . . 4 ⊢ (𝑅 ∈ Rels → (𝑅 ⊆ ◡𝑅 ↔ ∀𝑥∀𝑦(𝑥◡𝑅𝑦 → 𝑦◡𝑅𝑥))) | 
| 9 | relbrcnvg 6123 | . . . . . . 7 ⊢ (Rel 𝑅 → (𝑥◡𝑅𝑦 ↔ 𝑦𝑅𝑥)) | |
| 10 | 3, 9 | syl 17 | . . . . . 6 ⊢ (𝑅 ∈ Rels → (𝑥◡𝑅𝑦 ↔ 𝑦𝑅𝑥)) | 
| 11 | relbrcnvg 6123 | . . . . . . 7 ⊢ (Rel 𝑅 → (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦)) | |
| 12 | 3, 11 | syl 17 | . . . . . 6 ⊢ (𝑅 ∈ Rels → (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦)) | 
| 13 | 10, 12 | imbi12d 344 | . . . . 5 ⊢ (𝑅 ∈ Rels → ((𝑥◡𝑅𝑦 → 𝑦◡𝑅𝑥) ↔ (𝑦𝑅𝑥 → 𝑥𝑅𝑦))) | 
| 14 | 13 | 2albidv 1923 | . . . 4 ⊢ (𝑅 ∈ Rels → (∀𝑥∀𝑦(𝑥◡𝑅𝑦 → 𝑦◡𝑅𝑥) ↔ ∀𝑥∀𝑦(𝑦𝑅𝑥 → 𝑥𝑅𝑦))) | 
| 15 | 8, 14 | bitrd 279 | . . 3 ⊢ (𝑅 ∈ Rels → (𝑅 ⊆ ◡𝑅 ↔ ∀𝑥∀𝑦(𝑦𝑅𝑥 → 𝑥𝑅𝑦))) | 
| 16 | 2, 15 | anbi12d 632 | . 2 ⊢ (𝑅 ∈ Rels → ((◡𝑅 ⊆ 𝑅 ∧ 𝑅 ⊆ ◡𝑅) ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ ∀𝑥∀𝑦(𝑦𝑅𝑥 → 𝑥𝑅𝑦)))) | 
| 17 | eqss 3999 | . 2 ⊢ (◡𝑅 = 𝑅 ↔ (◡𝑅 ⊆ 𝑅 ∧ 𝑅 ⊆ ◡𝑅)) | |
| 18 | 2albiim 1890 | . 2 ⊢ (∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥) ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ ∀𝑥∀𝑦(𝑦𝑅𝑥 → 𝑥𝑅𝑦))) | |
| 19 | 16, 17, 18 | 3bitr4g 314 | 1 ⊢ (𝑅 ∈ Rels → (◡𝑅 = 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥))) | 
| Colors of variables: wff setvar class | 
| Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 ∀wal 1538 = wceq 1540 ∈ wcel 2108 ⊆ wss 3951 class class class wbr 5143 ◡ccnv 5684 Rel wrel 5690 Rels crels 38184 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-ext 2708 ax-sep 5296 ax-nul 5306 ax-pr 5432 | 
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3an 1089 df-tru 1543 df-fal 1553 df-ex 1780 df-sb 2065 df-clab 2715 df-cleq 2729 df-clel 2816 df-ral 3062 df-rex 3071 df-rab 3437 df-v 3482 df-dif 3954 df-un 3956 df-ss 3968 df-nul 4334 df-if 4526 df-pw 4602 df-sn 4627 df-pr 4629 df-op 4633 df-br 5144 df-opab 5206 df-xp 5691 df-rel 5692 df-cnv 5693 df-rels 38486 | 
| This theorem is referenced by: elrelscnveq4 38495 dfsymrels5 38549 | 
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