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Mirrors > Home > MPE Home > Th. List > lsw | Structured version Visualization version GIF version |
Description: Extract the last symbol of a word. May be not meaningful for other sets which are not words. (Contributed by Alexander van der Vekens, 18-Mar-2018.) |
Ref | Expression |
---|---|
lsw | ⊢ (𝑊 ∈ 𝑋 → (lastS‘𝑊) = (𝑊‘((♯‘𝑊) − 1))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex 3459 | . 2 ⊢ (𝑊 ∈ 𝑋 → 𝑊 ∈ V) | |
2 | fvex 6658 | . 2 ⊢ (𝑊‘((♯‘𝑊) − 1)) ∈ V | |
3 | id 22 | . . . 4 ⊢ (𝑤 = 𝑊 → 𝑤 = 𝑊) | |
4 | fveq2 6645 | . . . . 5 ⊢ (𝑤 = 𝑊 → (♯‘𝑤) = (♯‘𝑊)) | |
5 | 4 | oveq1d 7150 | . . . 4 ⊢ (𝑤 = 𝑊 → ((♯‘𝑤) − 1) = ((♯‘𝑊) − 1)) |
6 | 3, 5 | fveq12d 6652 | . . 3 ⊢ (𝑤 = 𝑊 → (𝑤‘((♯‘𝑤) − 1)) = (𝑊‘((♯‘𝑊) − 1))) |
7 | df-lsw 13906 | . . 3 ⊢ lastS = (𝑤 ∈ V ↦ (𝑤‘((♯‘𝑤) − 1))) | |
8 | 6, 7 | fvmptg 6743 | . 2 ⊢ ((𝑊 ∈ V ∧ (𝑊‘((♯‘𝑊) − 1)) ∈ V) → (lastS‘𝑊) = (𝑊‘((♯‘𝑊) − 1))) |
9 | 1, 2, 8 | sylancl 589 | 1 ⊢ (𝑊 ∈ 𝑋 → (lastS‘𝑊) = (𝑊‘((♯‘𝑊) − 1))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1538 ∈ wcel 2111 Vcvv 3441 ‘cfv 6324 (class class class)co 7135 1c1 10527 − cmin 10859 ♯chash 13686 lastSclsw 13905 |
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-mo 2598 df-eu 2629 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-ral 3111 df-rex 3112 df-v 3443 df-sbc 3721 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-uni 4801 df-br 5031 df-opab 5093 df-mpt 5111 df-id 5425 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-iota 6283 df-fun 6326 df-fv 6332 df-ov 7138 df-lsw 13906 |
This theorem is referenced by: lsw0 13908 lsw1 13910 lswcl 13911 ccatval1lsw 13929 lswccatn0lsw 13936 swrdlsw 14020 pfxfvlsw 14048 repswlsw 14135 lswcshw 14168 lswco 14192 lsws2 14257 lsws3 14258 lsws4 14259 wrdl2exs2 14299 swrd2lsw 14305 psgnunilem5 18614 wlkonwlk1l 27453 wwlknlsw 27633 wwlksnext 27679 wwlksnredwwlkn 27681 wwlksnextproplem2 27696 clwlkclwwlklem2a1 27777 clwlkclwwlklem2a3 27779 clwlkclwwlklem2a4 27782 clwlkclwwlklem2 27785 clwwisshclwwslem 27799 clwwlknlbonbgr1 27824 clwwlkn2 27829 clwwlkel 27831 clwwlkf 27832 clwwlkwwlksb 27839 clwwlknonex2lem2 27893 2clwwlk2clwwlklem 28131 numclwwlk1lem2f1 28142 pfxlsw2ccat 30652 iwrdsplit 31755 signsvtn0 31950 signstfveq0 31957 lswn0 43961 |
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