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Mirrors > Home > MPE Home > Th. List > resabs1 | Structured version Visualization version GIF version |
Description: Absorption law for restriction. Exercise 17 of [TakeutiZaring] p. 25. (Contributed by NM, 9-Aug-1994.) |
Ref | Expression |
---|---|
resabs1 | ⊢ (𝐵 ⊆ 𝐶 → ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | resres 5831 | . 2 ⊢ ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ (𝐶 ∩ 𝐵)) | |
2 | sseqin2 4142 | . . 3 ⊢ (𝐵 ⊆ 𝐶 ↔ (𝐶 ∩ 𝐵) = 𝐵) | |
3 | reseq2 5813 | . . 3 ⊢ ((𝐶 ∩ 𝐵) = 𝐵 → (𝐴 ↾ (𝐶 ∩ 𝐵)) = (𝐴 ↾ 𝐵)) | |
4 | 2, 3 | sylbi 220 | . 2 ⊢ (𝐵 ⊆ 𝐶 → (𝐴 ↾ (𝐶 ∩ 𝐵)) = (𝐴 ↾ 𝐵)) |
5 | 1, 4 | syl5eq 2845 | 1 ⊢ (𝐵 ⊆ 𝐶 → ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1538 ∩ cin 3880 ⊆ wss 3881 ↾ cres 5521 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2158 ax-12 2175 ax-ext 2770 ax-sep 5167 ax-nul 5174 ax-pr 5295 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3an 1086 df-tru 1541 df-ex 1782 df-nf 1786 df-sb 2070 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-rab 3115 df-v 3443 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-nul 4244 df-if 4426 df-sn 4526 df-pr 4528 df-op 4532 df-opab 5093 df-xp 5525 df-rel 5526 df-res 5531 |
This theorem is referenced by: resabs1d 5849 resabs2 5850 resiima 5911 fun2ssres 6369 fssres2 6520 smores3 7973 setsres 16517 gsum2dlem2 19084 lindsss 20513 resthauslem 21968 ptcmpfi 22418 tsmsres 22749 ressxms 23132 nrginvrcn 23298 xrge0gsumle 23438 lebnumii 23571 dvmptresicc 24519 dfrelog 25157 relogf1o 25158 dvlog 25242 dvlog2 25244 efopnlem2 25248 wilthlem2 25654 gsumle 30775 rrhre 31372 iwrdsplit 31755 rpsqrtcn 31974 pthhashvtx 32487 cvmsss2 32634 nosupres 33320 nosupbnd2lem1 33328 mbfposadd 35104 mzpcompact2lem 39692 eldioph2 39703 diophin 39713 diophrex 39716 2rexfrabdioph 39737 3rexfrabdioph 39738 4rexfrabdioph 39739 6rexfrabdioph 39740 7rexfrabdioph 39741 resabs1i 41782 fourierdlem46 42794 fourierdlem57 42805 fourierdlem111 42859 fouriersw 42873 psmeasurelem 43109 |
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