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Mirrors > Home > ILE Home > Th. List > dfss2 | Unicode version |
Description: Alternate definition of the subclass relationship between two classes. Definition 5.9 of [TakeutiZaring] p. 17. (Contributed by NM, 8-Jan-2002.) |
Ref | Expression |
---|---|
dfss2 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfss 2987 | . . 3 | |
2 | df-in 2979 | . . . 4 | |
3 | 2 | eqeq2i 2091 | . . 3 |
4 | abeq2 2187 | . . 3 | |
5 | 1, 3, 4 | 3bitri 204 | . 2 |
6 | pm4.71 381 | . . 3 | |
7 | 6 | albii 1399 | . 2 |
8 | 5, 7 | bitr4i 185 | 1 |
Colors of variables: wff set class |
Syntax hints: wi 4 wa 102 wb 103 wal 1282 wceq 1284 wcel 1433 cab 2067 cin 2972 wss 2973 |
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-5 1376 ax-7 1377 ax-gen 1378 ax-ie1 1422 ax-ie2 1423 ax-8 1435 ax-11 1437 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-nf 1390 df-sb 1686 df-clab 2068 df-cleq 2074 df-clel 2077 df-in 2979 df-ss 2986 |
This theorem is referenced by: dfss3 2989 dfss2f 2990 ssel 2993 ssriv 3003 ssrdv 3005 sstr2 3006 eqss 3014 nssr 3057 rabss2 3077 ssconb 3105 ssequn1 3142 unss 3146 ssin 3188 ssddif 3198 reldisj 3295 ssdif0im 3308 inssdif0im 3311 ssundifim 3326 sbcssg 3350 pwss 3397 snss 3516 snsssn 3553 ssuni 3623 unissb 3631 intss 3657 iunss 3719 dftr2 3877 axpweq 3945 axpow2 3950 ssextss 3975 ordunisuc2r 4258 setind 4282 zfregfr 4316 tfi 4323 ssrel 4446 ssrel2 4448 ssrelrel 4458 reliun 4476 relop 4504 issref 4727 funimass4 5245 isprm2 10499 bj-inf2vnlem3 10767 bj-inf2vnlem4 10768 |
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