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| Mirrors > Home > ILE Home > Th. List > prcssprc | GIF version | ||
| Description: The superclass of a proper class is a proper class. (Contributed by AV, 27-Dec-2020.) |
| Ref | Expression |
|---|---|
| prcssprc | ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ∉ V) → 𝐵 ∉ V) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ssexg 4223 | . . . 4 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐵 ∈ V) → 𝐴 ∈ V) | |
| 2 | 1 | ex 115 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → (𝐵 ∈ V → 𝐴 ∈ V)) |
| 3 | 2 | nelcon3d 2506 | . 2 ⊢ (𝐴 ⊆ 𝐵 → (𝐴 ∉ V → 𝐵 ∉ V)) |
| 4 | 3 | imp 124 | 1 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ∉ V) → 𝐵 ∉ V) |
| Colors of variables: wff set class |
| Syntax hints: → wi 4 ∧ wa 104 ∈ wcel 2200 ∉ wnel 2495 Vcvv 2799 ⊆ wss 3197 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 617 ax-in2 618 ax-io 714 ax-5 1493 ax-7 1494 ax-gen 1495 ax-ie1 1539 ax-ie2 1540 ax-8 1550 ax-10 1551 ax-11 1552 ax-i12 1553 ax-bndl 1555 ax-4 1556 ax-17 1572 ax-i9 1576 ax-ial 1580 ax-i5r 1581 ax-ext 2211 ax-sep 4202 |
| This theorem depends on definitions: df-bi 117 df-tru 1398 df-nf 1507 df-sb 1809 df-clab 2216 df-cleq 2222 df-clel 2225 df-nfc 2361 df-nel 2496 df-v 2801 df-in 3203 df-ss 3210 |
| This theorem is referenced by: usgrprc 16071 |
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