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| Mirrors > Home > MPE Home > Th. List > Mathboxes > n0elim | Structured version Visualization version GIF version | ||
| Description: Implication of that the empty set is not an element of a class. (Contributed by Peter Mazsa, 30-Dec-2024.) | 
| Ref | Expression | 
|---|---|
| n0elim | ⊢ (¬ ∅ ∈ 𝐴 → (dom (◡ E ↾ 𝐴) / (◡ E ↾ 𝐴)) = 𝐴) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | n0el2 38334 | . . . 4 ⊢ (¬ ∅ ∈ 𝐴 ↔ dom (◡ E ↾ 𝐴) = 𝐴) | |
| 2 | 1 | biimpi 216 | . . 3 ⊢ (¬ ∅ ∈ 𝐴 → dom (◡ E ↾ 𝐴) = 𝐴) | 
| 3 | 2 | qseq1d 8804 | . 2 ⊢ (¬ ∅ ∈ 𝐴 → (dom (◡ E ↾ 𝐴) / (◡ E ↾ 𝐴)) = (𝐴 / (◡ E ↾ 𝐴))) | 
| 4 | qsresid 38326 | . . 3 ⊢ (𝐴 / (◡ E ↾ 𝐴)) = (𝐴 / ◡ E ) | |
| 5 | qsid 8823 | . . 3 ⊢ (𝐴 / ◡ E ) = 𝐴 | |
| 6 | 4, 5 | eqtri 2765 | . 2 ⊢ (𝐴 / (◡ E ↾ 𝐴)) = 𝐴 | 
| 7 | 3, 6 | eqtrdi 2793 | 1 ⊢ (¬ ∅ ∈ 𝐴 → (dom (◡ E ↾ 𝐴) / (◡ E ↾ 𝐴)) = 𝐴) | 
| Colors of variables: wff setvar class | 
| Syntax hints: ¬ wn 3 → wi 4 = wceq 1540 ∈ wcel 2108 ∅c0 4333 E cep 5583 ◡ccnv 5684 dom cdm 5685 ↾ cres 5687 / cqs 8744 | 
| 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-10 2141 ax-11 2157 ax-12 2177 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-nf 1784 df-sb 2065 df-mo 2540 df-eu 2569 df-clab 2715 df-cleq 2729 df-clel 2816 df-nfc 2892 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-br 5144 df-opab 5206 df-eprel 5584 df-xp 5691 df-rel 5692 df-cnv 5693 df-dm 5695 df-rn 5696 df-res 5697 df-ima 5698 df-ec 8747 df-qs 8751 | 
| This theorem is referenced by: n0el3 38652 | 
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