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| Mirrors > Home > MPE Home > Th. List > Mathboxes > dfint3 | Structured version Visualization version GIF version | ||
| Description: Quantifier-free definition of class intersection. (Contributed by Scott Fenton, 13-Apr-2018.) |
| Ref | Expression |
|---|---|
| dfint3 | ⊢ ∩ 𝐴 = (V ∖ (◡(V ∖ E ) “ 𝐴)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | dfint2 4948 | . 2 ⊢ ∩ 𝐴 = {𝑥 ∣ ∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦} | |
| 2 | ralnex 3072 | . . . 4 ⊢ (∀𝑦 ∈ 𝐴 ¬ 𝑦◡(V ∖ E )𝑥 ↔ ¬ ∃𝑦 ∈ 𝐴 𝑦◡(V ∖ E )𝑥) | |
| 3 | vex 3484 | . . . . . . . . 9 ⊢ 𝑦 ∈ V | |
| 4 | vex 3484 | . . . . . . . . 9 ⊢ 𝑥 ∈ V | |
| 5 | 3, 4 | brcnv 5893 | . . . . . . . 8 ⊢ (𝑦◡(V ∖ E )𝑥 ↔ 𝑥(V ∖ E )𝑦) |
| 6 | brv 5477 | . . . . . . . . 9 ⊢ 𝑥V𝑦 | |
| 7 | brdif 5196 | . . . . . . . . 9 ⊢ (𝑥(V ∖ E )𝑦 ↔ (𝑥V𝑦 ∧ ¬ 𝑥 E 𝑦)) | |
| 8 | 6, 7 | mpbiran 709 | . . . . . . . 8 ⊢ (𝑥(V ∖ E )𝑦 ↔ ¬ 𝑥 E 𝑦) |
| 9 | 5, 8 | bitr2i 276 | . . . . . . 7 ⊢ (¬ 𝑥 E 𝑦 ↔ 𝑦◡(V ∖ E )𝑥) |
| 10 | 9 | con1bii 356 | . . . . . 6 ⊢ (¬ 𝑦◡(V ∖ E )𝑥 ↔ 𝑥 E 𝑦) |
| 11 | epel 5587 | . . . . . 6 ⊢ (𝑥 E 𝑦 ↔ 𝑥 ∈ 𝑦) | |
| 12 | 10, 11 | bitr2i 276 | . . . . 5 ⊢ (𝑥 ∈ 𝑦 ↔ ¬ 𝑦◡(V ∖ E )𝑥) |
| 13 | 12 | ralbii 3093 | . . . 4 ⊢ (∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦 ↔ ∀𝑦 ∈ 𝐴 ¬ 𝑦◡(V ∖ E )𝑥) |
| 14 | eldif 3961 | . . . . . 6 ⊢ (𝑥 ∈ (V ∖ (◡(V ∖ E ) “ 𝐴)) ↔ (𝑥 ∈ V ∧ ¬ 𝑥 ∈ (◡(V ∖ E ) “ 𝐴))) | |
| 15 | 4, 14 | mpbiran 709 | . . . . 5 ⊢ (𝑥 ∈ (V ∖ (◡(V ∖ E ) “ 𝐴)) ↔ ¬ 𝑥 ∈ (◡(V ∖ E ) “ 𝐴)) |
| 16 | 4 | elima 6083 | . . . . 5 ⊢ (𝑥 ∈ (◡(V ∖ E ) “ 𝐴) ↔ ∃𝑦 ∈ 𝐴 𝑦◡(V ∖ E )𝑥) |
| 17 | 15, 16 | xchbinx 334 | . . . 4 ⊢ (𝑥 ∈ (V ∖ (◡(V ∖ E ) “ 𝐴)) ↔ ¬ ∃𝑦 ∈ 𝐴 𝑦◡(V ∖ E )𝑥) |
| 18 | 2, 13, 17 | 3bitr4ri 304 | . . 3 ⊢ (𝑥 ∈ (V ∖ (◡(V ∖ E ) “ 𝐴)) ↔ ∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) |
| 19 | 18 | eqabi 2877 | . 2 ⊢ (V ∖ (◡(V ∖ E ) “ 𝐴)) = {𝑥 ∣ ∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦} |
| 20 | 1, 19 | eqtr4i 2768 | 1 ⊢ ∩ 𝐴 = (V ∖ (◡(V ∖ E ) “ 𝐴)) |
| Colors of variables: wff setvar class |
| Syntax hints: ¬ wn 3 = wceq 1540 ∈ wcel 2108 {cab 2714 ∀wral 3061 ∃wrex 3070 Vcvv 3480 ∖ cdif 3948 ∩ cint 4946 class class class wbr 5143 E cep 5583 ◡ccnv 5684 “ cima 5688 |
| 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-ne 2941 df-ral 3062 df-rex 3071 df-rab 3437 df-v 3482 df-dif 3954 df-un 3956 df-in 3958 df-ss 3968 df-nul 4334 df-if 4526 df-sn 4627 df-pr 4629 df-op 4633 df-int 4947 df-br 5144 df-opab 5206 df-eprel 5584 df-xp 5691 df-cnv 5693 df-dm 5695 df-rn 5696 df-res 5697 df-ima 5698 |
| This theorem is referenced by: (None) |
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