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Mirrors > Home > ILE Home > Th. List > eldifsn | GIF version |
Description: Membership in a set with an element removed. (Contributed by NM, 10-Oct-2007.) |
Ref | Expression |
---|---|
eldifsn | ⊢ (𝐴 ∈ (𝐵 ∖ {𝐶}) ↔ (𝐴 ∈ 𝐵 ∧ 𝐴 ≠ 𝐶)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eldif 2927 | . 2 ⊢ (𝐴 ∈ (𝐵 ∖ {𝐶}) ↔ (𝐴 ∈ 𝐵 ∧ ¬ 𝐴 ∈ {𝐶})) | |
2 | elsng 3390 | . . . 4 ⊢ (𝐴 ∈ 𝐵 → (𝐴 ∈ {𝐶} ↔ 𝐴 = 𝐶)) | |
3 | 2 | necon3bbid 2245 | . . 3 ⊢ (𝐴 ∈ 𝐵 → (¬ 𝐴 ∈ {𝐶} ↔ 𝐴 ≠ 𝐶)) |
4 | 3 | pm5.32i 427 | . 2 ⊢ ((𝐴 ∈ 𝐵 ∧ ¬ 𝐴 ∈ {𝐶}) ↔ (𝐴 ∈ 𝐵 ∧ 𝐴 ≠ 𝐶)) |
5 | 1, 4 | bitri 173 | 1 ⊢ (𝐴 ∈ (𝐵 ∖ {𝐶}) ↔ (𝐴 ∈ 𝐵 ∧ 𝐴 ≠ 𝐶)) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 ∧ wa 97 ↔ wb 98 ∈ wcel 1393 ≠ wne 2204 ∖ cdif 2914 {csn 3375 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 ax-io 630 ax-5 1336 ax-7 1337 ax-gen 1338 ax-ie1 1382 ax-ie2 1383 ax-8 1395 ax-10 1396 ax-11 1397 ax-i12 1398 ax-bndl 1399 ax-4 1400 ax-17 1419 ax-i9 1423 ax-ial 1427 ax-i5r 1428 ax-ext 2022 |
This theorem depends on definitions: df-bi 110 df-tru 1246 df-nf 1350 df-sb 1646 df-clab 2027 df-cleq 2033 df-clel 2036 df-nfc 2167 df-ne 2206 df-v 2559 df-dif 2920 df-sn 3381 |
This theorem is referenced by: eldifsni 3496 rexdifsn 3499 difsn 3501 fnniniseg2 5290 rexsupp 5291 suppssfv 5708 suppssov1 5709 dif1o 6021 fidifsnen 6331 elni 6406 divvalap 7653 elnnne0 8195 divfnzn 8556 |
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