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Mirrors > Home > ILE Home > Th. List > nfunsn | Unicode version |
Description: If the restriction of a class to a singleton is not a function, its value is the empty set. (Contributed by NM, 8-Aug-2010.) (Proof shortened by Andrew Salmon, 22-Oct-2011.) |
Ref | Expression |
---|---|
nfunsn |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eumo 1973 | . . . . . . 7 | |
2 | vex 2604 | . . . . . . . . . 10 | |
3 | 2 | brres 4636 | . . . . . . . . 9 |
4 | velsn 3415 | . . . . . . . . . . 11 | |
5 | breq1 3788 | . . . . . . . . . . 11 | |
6 | 4, 5 | sylbi 119 | . . . . . . . . . 10 |
7 | 6 | biimpac 292 | . . . . . . . . 9 |
8 | 3, 7 | sylbi 119 | . . . . . . . 8 |
9 | 8 | moimi 2006 | . . . . . . 7 |
10 | 1, 9 | syl 14 | . . . . . 6 |
11 | 10 | alrimiv 1795 | . . . . 5 |
12 | relres 4657 | . . . . 5 | |
13 | 11, 12 | jctil 305 | . . . 4 |
14 | dffun6 4936 | . . . 4 | |
15 | 13, 14 | sylibr 132 | . . 3 |
16 | 15 | con3i 594 | . 2 |
17 | tz6.12-2 5189 | . 2 | |
18 | 16, 17 | syl 14 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wi 4 wa 102 wb 103 wal 1282 wceq 1284 wcel 1433 weu 1941 wmo 1942 c0 3251 csn 3398 class class class wbr 3785 cres 4365 wrel 4368 wfun 4916 cfv 4922 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in1 576 ax-in2 577 ax-io 662 ax-5 1376 ax-7 1377 ax-gen 1378 ax-ie1 1422 ax-ie2 1423 ax-8 1435 ax-10 1436 ax-11 1437 ax-i12 1438 ax-bndl 1439 ax-4 1440 ax-14 1445 ax-17 1459 ax-i9 1463 ax-ial 1467 ax-i5r 1468 ax-ext 2063 ax-sep 3896 ax-pow 3948 ax-pr 3964 |
This theorem depends on definitions: df-bi 115 df-3an 921 df-tru 1287 df-fal 1290 df-nf 1390 df-sb 1686 df-eu 1944 df-mo 1945 df-clab 2068 df-cleq 2074 df-clel 2077 df-nfc 2208 df-ral 2353 df-rex 2354 df-v 2603 df-dif 2975 df-un 2977 df-in 2979 df-ss 2986 df-nul 3252 df-pw 3384 df-sn 3404 df-pr 3405 df-op 3407 df-uni 3602 df-br 3786 df-opab 3840 df-id 4048 df-xp 4369 df-rel 4370 df-cnv 4371 df-co 4372 df-res 4375 df-iota 4887 df-fun 4924 df-fv 4930 |
This theorem is referenced by: (None) |
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