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Mirrors > Home > ILE Home > Th. List > difidALT | Unicode version |
Description: The difference between a class and itself is the empty set. Proposition 5.15 of [TakeutiZaring] p. 20. Also Theorem 32 of [Suppes] p. 28. Alternate proof of difid 3436. (Contributed by David Abernethy, 17-Jun-2012.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
difidALT |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfdif2 3084 | . 2 | |
2 | dfnul3 3371 | . 2 | |
3 | 1, 2 | eqtr4i 2164 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wceq 1332 wcel 1481 crab 2421 cdif 3073 c0 3368 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 604 ax-in2 605 ax-io 699 ax-5 1424 ax-7 1425 ax-gen 1426 ax-ie1 1470 ax-ie2 1471 ax-8 1483 ax-10 1484 ax-11 1485 ax-i12 1486 ax-bndl 1487 ax-4 1488 ax-17 1507 ax-i9 1511 ax-ial 1515 ax-i5r 1516 ax-ext 2122 |
This theorem depends on definitions: df-bi 116 df-tru 1335 df-nf 1438 df-sb 1737 df-clab 2127 df-cleq 2133 df-clel 2136 df-nfc 2271 df-rab 2426 df-v 2691 df-dif 3078 df-nul 3369 |
This theorem is referenced by: (None) |
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