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Mirrors > Home > ILE Home > Th. List > phplem1 | Unicode version |
Description: Lemma for Pigeonhole Principle. If we join a natural number to itself minus an element, we end up with its successor minus the same element. (Contributed by NM, 25-May-1998.) |
Ref | Expression |
---|---|
phplem1 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nnord 4495 | . . 3 | |
2 | nordeq 4429 | . . . 4 | |
3 | disjsn2 3556 | . . . 4 | |
4 | 2, 3 | syl 14 | . . 3 |
5 | 1, 4 | sylan 281 | . 2 |
6 | undif4 3395 | . . 3 | |
7 | df-suc 4263 | . . . . 5 | |
8 | 7 | equncomi 3192 | . . . 4 |
9 | 8 | difeq1i 3160 | . . 3 |
10 | 6, 9 | syl6eqr 2168 | . 2 |
11 | 5, 10 | syl 14 | 1 |
Colors of variables: wff set class |
Syntax hints: wi 4 wa 103 wceq 1316 wcel 1465 wne 2285 cdif 3038 cun 3039 cin 3040 c0 3333 csn 3497 word 4254 csuc 4257 com 4474 |
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 588 ax-in2 589 ax-io 683 ax-5 1408 ax-7 1409 ax-gen 1410 ax-ie1 1454 ax-ie2 1455 ax-8 1467 ax-10 1468 ax-11 1469 ax-i12 1470 ax-bndl 1471 ax-4 1472 ax-13 1476 ax-14 1477 ax-17 1491 ax-i9 1495 ax-ial 1499 ax-i5r 1500 ax-ext 2099 ax-sep 4016 ax-nul 4024 ax-pow 4068 ax-pr 4101 ax-un 4325 ax-setind 4422 ax-iinf 4472 |
This theorem depends on definitions: df-bi 116 df-3an 949 df-tru 1319 df-fal 1322 df-nf 1422 df-sb 1721 df-clab 2104 df-cleq 2110 df-clel 2113 df-nfc 2247 df-ne 2286 df-ral 2398 df-rex 2399 df-rab 2402 df-v 2662 df-dif 3043 df-un 3045 df-in 3047 df-ss 3054 df-nul 3334 df-pw 3482 df-sn 3503 df-pr 3504 df-uni 3707 df-int 3742 df-tr 3997 df-iord 4258 df-on 4260 df-suc 4263 df-iom 4475 |
This theorem is referenced by: phplem2 6715 |
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