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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 7465 | . 2 ⊢ ((𝐴 ∈ V ∧ {𝐴} ∈ V) ↔ (𝐴 ∪ {𝐴}) ∈ V) | |
2 | snex 5323 | . . 3 ⊢ {𝐴} ∈ V | |
3 | 2 | biantru 532 | . 2 ⊢ (𝐴 ∈ V ↔ (𝐴 ∈ V ∧ {𝐴} ∈ V)) |
4 | df-suc 6191 | . . 3 ⊢ suc 𝐴 = (𝐴 ∪ {𝐴}) | |
5 | 4 | eleq1i 2903 | . 2 ⊢ (suc 𝐴 ∈ V ↔ (𝐴 ∪ {𝐴}) ∈ V) |
6 | 1, 3, 5 | 3bitr4i 305 | 1 ⊢ (𝐴 ∈ V ↔ suc 𝐴 ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 208 ∧ wa 398 ∈ wcel 2110 Vcvv 3494 ∪ cun 3933 {csn 4560 suc csuc 6187 |
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 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5195 ax-nul 5202 ax-pr 5321 ax-un 7455 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-rex 3144 df-rab 3147 df-v 3496 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-nul 4291 df-sn 4561 df-pr 4563 df-uni 4832 df-suc 6191 |
This theorem is referenced by: sucexg 7519 sucelon 7526 ordsucelsuc 7531 oeordi 8207 suc11reg 9076 rankxpsuc 9305 isf32lem2 9770 limsucncmpi 33788 |
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