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Mirrors > Home > ILE Home > Th. List > dfiota2 | Unicode version |
Description: Alternate definition for descriptions. Definition 8.18 in [Quine] p. 56. (Contributed by Andrew Salmon, 30-Jun-2011.) |
Ref | Expression |
---|---|
dfiota2 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-iota 4887 | . 2 | |
2 | df-sn 3404 | . . . . . 6 | |
3 | 2 | eqeq2i 2091 | . . . . 5 |
4 | abbi 2192 | . . . . 5 | |
5 | 3, 4 | bitr4i 185 | . . . 4 |
6 | 5 | abbii 2194 | . . 3 |
7 | 6 | unieqi 3611 | . 2 |
8 | 1, 7 | eqtri 2101 | 1 |
Colors of variables: wff set class |
Syntax hints: wb 103 wal 1282 wceq 1284 cab 2067 csn 3398 cuni 3601 cio 4885 |
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-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-17 1459 ax-i9 1463 ax-ial 1467 ax-i5r 1468 ax-ext 2063 |
This theorem depends on definitions: df-bi 115 df-tru 1287 df-nf 1390 df-sb 1686 df-clab 2068 df-cleq 2074 df-clel 2077 df-nfc 2208 df-rex 2354 df-sn 3404 df-uni 3602 df-iota 4887 |
This theorem is referenced by: nfiota1 4889 nfiotadxy 4890 cbviota 4892 sb8iota 4894 iotaval 4898 iotanul 4902 fv2 5193 |
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