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Mirrors > Home > MPE Home > Th. List > sucexb | Structured version Visualization version GIF version |
Description: A successor exists iff its class argument exists. (Contributed by NM, 22-Jun-1998.) |
Ref | Expression |
---|---|
sucexb | ⊢ (𝐴 ∈ V ↔ suc 𝐴 ∈ V) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | unexb 7766 | . 2 ⊢ ((𝐴 ∈ V ∧ {𝐴} ∈ V) ↔ (𝐴 ∪ {𝐴}) ∈ V) | |
2 | snex 5442 | . . 3 ⊢ {𝐴} ∈ V | |
3 | 2 | biantru 529 | . 2 ⊢ (𝐴 ∈ V ↔ (𝐴 ∈ V ∧ {𝐴} ∈ V)) |
4 | df-suc 6392 | . . 3 ⊢ suc 𝐴 = (𝐴 ∪ {𝐴}) | |
5 | 4 | eleq1i 2830 | . 2 ⊢ (suc 𝐴 ∈ V ↔ (𝐴 ∪ {𝐴}) ∈ V) |
6 | 1, 3, 5 | 3bitr4i 303 | 1 ⊢ (𝐴 ∈ V ↔ suc 𝐴 ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 206 ∧ wa 395 ∈ wcel 2106 Vcvv 3478 ∪ cun 3961 {csn 4631 suc csuc 6388 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-ext 2706 ax-sep 5302 ax-nul 5312 ax-pr 5438 ax-un 7754 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-sb 2063 df-clab 2713 df-cleq 2727 df-clel 2814 df-rab 3434 df-v 3480 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-nul 4340 df-sn 4632 df-pr 4634 df-uni 4913 df-suc 6392 |
This theorem is referenced by: sucexg 7825 onsucb 7837 ordsucelsuc 7842 oeordi 8624 suc11reg 9657 rankxpsuc 9920 isf32lem2 10392 limsucncmpi 36428 |
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