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Mirrors > Home > MPE Home > Th. List > cnvsym | Structured version Visualization version GIF version |
Description: Two ways of saying a relation is symmetric. Similar to definition of symmetry in [Schechter] p. 51. (Contributed by NM, 28-Dec-1996.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) (Proof shortened by SN, 23-Dec-2024.) Avoid ax-11 2155. (Revised by BTernaryTau, 29-Dec-2024.) |
Ref | Expression |
---|---|
cnvsym | ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | relcnv 6061 | . . 3 ⊢ Rel ◡𝑅 | |
2 | ssrel3 5747 | . . 3 ⊢ (Rel ◡𝑅 → (◡𝑅 ⊆ 𝑅 ↔ ∀𝑦∀𝑥(𝑦◡𝑅𝑥 → 𝑦𝑅𝑥))) | |
3 | 1, 2 | ax-mp 5 | . 2 ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑦∀𝑥(𝑦◡𝑅𝑥 → 𝑦𝑅𝑥)) |
4 | breq1 5113 | . . . 4 ⊢ (𝑦 = 𝑧 → (𝑦◡𝑅𝑥 ↔ 𝑧◡𝑅𝑥)) | |
5 | breq1 5113 | . . . 4 ⊢ (𝑦 = 𝑧 → (𝑦𝑅𝑥 ↔ 𝑧𝑅𝑥)) | |
6 | 4, 5 | imbi12d 345 | . . 3 ⊢ (𝑦 = 𝑧 → ((𝑦◡𝑅𝑥 → 𝑦𝑅𝑥) ↔ (𝑧◡𝑅𝑥 → 𝑧𝑅𝑥))) |
7 | breq2 5114 | . . . 4 ⊢ (𝑥 = 𝑧 → (𝑦◡𝑅𝑥 ↔ 𝑦◡𝑅𝑧)) | |
8 | breq2 5114 | . . . 4 ⊢ (𝑥 = 𝑧 → (𝑦𝑅𝑥 ↔ 𝑦𝑅𝑧)) | |
9 | 7, 8 | imbi12d 345 | . . 3 ⊢ (𝑥 = 𝑧 → ((𝑦◡𝑅𝑥 → 𝑦𝑅𝑥) ↔ (𝑦◡𝑅𝑧 → 𝑦𝑅𝑧))) |
10 | 6, 9 | alcomw 2048 | . 2 ⊢ (∀𝑦∀𝑥(𝑦◡𝑅𝑥 → 𝑦𝑅𝑥) ↔ ∀𝑥∀𝑦(𝑦◡𝑅𝑥 → 𝑦𝑅𝑥)) |
11 | vex 3452 | . . . . 5 ⊢ 𝑦 ∈ V | |
12 | vex 3452 | . . . . 5 ⊢ 𝑥 ∈ V | |
13 | 11, 12 | brcnv 5843 | . . . 4 ⊢ (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦) |
14 | 13 | imbi1i 350 | . . 3 ⊢ ((𝑦◡𝑅𝑥 → 𝑦𝑅𝑥) ↔ (𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
15 | 14 | 2albii 1823 | . 2 ⊢ (∀𝑥∀𝑦(𝑦◡𝑅𝑥 → 𝑦𝑅𝑥) ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
16 | 3, 10, 15 | 3bitri 297 | 1 ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∀wal 1540 ⊆ wss 3915 class class class wbr 5110 ◡ccnv 5637 Rel wrel 5643 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-ext 2708 ax-sep 5261 ax-nul 5268 ax-pr 5389 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-sb 2069 df-clab 2715 df-cleq 2729 df-clel 2815 df-rab 3411 df-v 3450 df-dif 3918 df-un 3920 df-in 3922 df-ss 3932 df-nul 4288 df-if 4492 df-sn 4592 df-pr 4594 df-op 4598 df-br 5111 df-opab 5173 df-xp 5644 df-rel 5645 df-cnv 5646 |
This theorem is referenced by: dfer2 8656 relcnveq3 36811 relcnveq 36812 relcnveq2 36813 cnvcosseq 36928 symrelcoss2 36957 elrelscnveq3 36982 elrelscnveq 36983 elrelscnveq2 36984 dfsymrels3 37037 dfsymrel3 37041 symrefref3 37055 refsymrels3 37057 elrefsymrels3 37061 dfeqvrels3 37080 |
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