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Mirrors > Home > MPE Home > Th. List > co01 | Structured version Visualization version GIF version |
Description: Composition with the empty set. (Contributed by NM, 24-Apr-2004.) |
Ref | Expression |
---|---|
co01 | ⊢ (∅ ∘ 𝐴) = ∅ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cnv0 6079 | . . . 4 ⊢ ◡∅ = ∅ | |
2 | cnvco 5827 | . . . . 5 ⊢ ◡(∅ ∘ 𝐴) = (◡𝐴 ∘ ◡∅) | |
3 | 1 | coeq2i 5802 | . . . . 5 ⊢ (◡𝐴 ∘ ◡∅) = (◡𝐴 ∘ ∅) |
4 | co02 6198 | . . . . 5 ⊢ (◡𝐴 ∘ ∅) = ∅ | |
5 | 2, 3, 4 | 3eqtri 2768 | . . . 4 ⊢ ◡(∅ ∘ 𝐴) = ∅ |
6 | 1, 5 | eqtr4i 2767 | . . 3 ⊢ ◡∅ = ◡(∅ ∘ 𝐴) |
7 | 6 | cnveqi 5816 | . 2 ⊢ ◡◡∅ = ◡◡(∅ ∘ 𝐴) |
8 | rel0 5741 | . . 3 ⊢ Rel ∅ | |
9 | dfrel2 6127 | . . 3 ⊢ (Rel ∅ ↔ ◡◡∅ = ∅) | |
10 | 8, 9 | mpbi 229 | . 2 ⊢ ◡◡∅ = ∅ |
11 | relco 6046 | . . 3 ⊢ Rel (∅ ∘ 𝐴) | |
12 | dfrel2 6127 | . . 3 ⊢ (Rel (∅ ∘ 𝐴) ↔ ◡◡(∅ ∘ 𝐴) = (∅ ∘ 𝐴)) | |
13 | 11, 12 | mpbi 229 | . 2 ⊢ ◡◡(∅ ∘ 𝐴) = (∅ ∘ 𝐴) |
14 | 7, 10, 13 | 3eqtr3ri 2773 | 1 ⊢ (∅ ∘ 𝐴) = ∅ |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1540 ∅c0 4269 ◡ccnv 5619 ∘ ccom 5624 Rel wrel 5625 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1912 ax-6 1970 ax-7 2010 ax-8 2107 ax-9 2115 ax-12 2170 ax-ext 2707 ax-sep 5243 ax-nul 5250 ax-pr 5372 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1781 df-sb 2067 df-clab 2714 df-cleq 2728 df-clel 2814 df-rab 3404 df-v 3443 df-dif 3901 df-un 3903 df-in 3905 df-ss 3915 df-nul 4270 df-if 4474 df-sn 4574 df-pr 4576 df-op 4580 df-br 5093 df-opab 5155 df-xp 5626 df-rel 5627 df-cnv 5628 df-co 5629 |
This theorem is referenced by: xpcoid 6228 0trrel 14791 relexpsucrd 14843 relexpaddd 14864 gsumval3 19603 utop2nei 23508 cononrel2 41532 |
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