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Mirrors > Home > MPE Home > Th. List > difsnexi | Structured version Visualization version Unicode version |
Description: If the difference of a class and a singleton is a set, the class itself is a set. (Contributed by AV, 15-Jan-2019.) |
Ref | Expression |
---|---|
difsnexi |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr 477 | . . . . 5 | |
2 | snex 4908 | . . . . 5 | |
3 | unexg 6959 | . . . . 5 | |
4 | 1, 2, 3 | sylancl 694 | . . . 4 |
5 | difsnid 4341 | . . . . . . 7 | |
6 | 5 | eqcomd 2628 | . . . . . 6 |
7 | 6 | eleq1d 2686 | . . . . 5 |
8 | 7 | adantr 481 | . . . 4 |
9 | 4, 8 | mpbird 247 | . . 3 |
10 | 9 | ex 450 | . 2 |
11 | difsn 4328 | . . . 4 | |
12 | 11 | eleq1d 2686 | . . 3 |
13 | 12 | biimpd 219 | . 2 |
14 | 10, 13 | pm2.61i 176 | 1 |
Colors of variables: wff setvar class |
Syntax hints: wn 3 wi 4 wb 196 wa 384 wcel 1990 cvv 3200 cdif 3571 cun 3572 csn 4177 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pr 4906 ax-un 6949 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-ral 2917 df-rex 2918 df-rab 2921 df-v 3202 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-nul 3916 df-sn 4178 df-pr 4180 df-uni 4437 |
This theorem is referenced by: pmtrdifellem1 17896 pmtrdifellem2 17897 tgdif0 20796 |
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