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Mirrors > Home > ILE Home > Th. List > pwntru | GIF version |
Description: A slight strengthening of pwtrufal 13192. (Contributed by Mario Carneiro and Jim Kingdon, 12-Sep-2023.) |
Ref | Expression |
---|---|
pwntru | ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → 𝐴 = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr 109 | . . . 4 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → 𝐴 ≠ {∅}) | |
2 | 1 | neneqd 2329 | . . 3 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → ¬ 𝐴 = {∅}) |
3 | simpll 518 | . . . . . 6 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → 𝐴 ⊆ {∅}) | |
4 | simpl 108 | . . . . . . . . . 10 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → 𝐴 ⊆ {∅}) | |
5 | 4 | sselda 3097 | . . . . . . . . 9 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ {∅}) |
6 | elsni 3545 | . . . . . . . . 9 ⊢ (𝑥 ∈ {∅} → 𝑥 = ∅) | |
7 | 5, 6 | syl 14 | . . . . . . . 8 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → 𝑥 = ∅) |
8 | simpr 109 | . . . . . . . 8 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ 𝐴) | |
9 | 7, 8 | eqeltrrd 2217 | . . . . . . 7 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → ∅ ∈ 𝐴) |
10 | 9 | snssd 3665 | . . . . . 6 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → {∅} ⊆ 𝐴) |
11 | 3, 10 | eqssd 3114 | . . . . 5 ⊢ (((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) ∧ 𝑥 ∈ 𝐴) → 𝐴 = {∅}) |
12 | 11 | ex 114 | . . . 4 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → (𝑥 ∈ 𝐴 → 𝐴 = {∅})) |
13 | 12 | exlimdv 1791 | . . 3 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → (∃𝑥 𝑥 ∈ 𝐴 → 𝐴 = {∅})) |
14 | 2, 13 | mtod 652 | . 2 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → ¬ ∃𝑥 𝑥 ∈ 𝐴) |
15 | notm0 3383 | . 2 ⊢ (¬ ∃𝑥 𝑥 ∈ 𝐴 ↔ 𝐴 = ∅) | |
16 | 14, 15 | sylib 121 | 1 ⊢ ((𝐴 ⊆ {∅} ∧ 𝐴 ≠ {∅}) → 𝐴 = ∅) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 103 = wceq 1331 ∃wex 1468 ∈ wcel 1480 ≠ wne 2308 ⊆ wss 3071 ∅c0 3363 {csn 3527 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 603 ax-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 |
This theorem depends on definitions: df-bi 116 df-tru 1334 df-fal 1337 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ne 2309 df-v 2688 df-dif 3073 df-in 3077 df-ss 3084 df-nul 3364 df-sn 3533 |
This theorem is referenced by: exmid1dc 4123 exmid1stab 13195 |
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