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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 3512 | . 2 ⊢ (𝑊 ∈ 𝑋 → 𝑊 ∈ V) | |
2 | fvex 6682 | . 2 ⊢ (𝑊‘((♯‘𝑊) − 1)) ∈ V | |
3 | id 22 | . . . 4 ⊢ (𝑤 = 𝑊 → 𝑤 = 𝑊) | |
4 | fveq2 6669 | . . . . 5 ⊢ (𝑤 = 𝑊 → (♯‘𝑤) = (♯‘𝑊)) | |
5 | 4 | oveq1d 7170 | . . . 4 ⊢ (𝑤 = 𝑊 → ((♯‘𝑤) − 1) = ((♯‘𝑊) − 1)) |
6 | 3, 5 | fveq12d 6676 | . . 3 ⊢ (𝑤 = 𝑊 → (𝑤‘((♯‘𝑤) − 1)) = (𝑊‘((♯‘𝑊) − 1))) |
7 | df-lsw 13914 | . . 3 ⊢ lastS = (𝑤 ∈ V ↦ (𝑤‘((♯‘𝑤) − 1))) | |
8 | 6, 7 | fvmptg 6765 | . 2 ⊢ ((𝑊 ∈ V ∧ (𝑊‘((♯‘𝑊) − 1)) ∈ V) → (lastS‘𝑊) = (𝑊‘((♯‘𝑊) − 1))) |
9 | 1, 2, 8 | sylancl 588 | 1 ⊢ (𝑊 ∈ 𝑋 → (lastS‘𝑊) = (𝑊‘((♯‘𝑊) − 1))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1533 ∈ wcel 2110 Vcvv 3494 ‘cfv 6354 (class class class)co 7155 1c1 10537 − cmin 10869 ♯chash 13689 lastSclsw 13913 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5202 ax-nul 5209 ax-pr 5329 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ral 3143 df-rex 3144 df-rab 3147 df-v 3496 df-sbc 3772 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-nul 4291 df-if 4467 df-sn 4567 df-pr 4569 df-op 4573 df-uni 4838 df-br 5066 df-opab 5128 df-mpt 5146 df-id 5459 df-xp 5560 df-rel 5561 df-cnv 5562 df-co 5563 df-dm 5564 df-iota 6313 df-fun 6356 df-fv 6362 df-ov 7158 df-lsw 13914 |
This theorem is referenced by: lsw0 13916 lsw1 13918 lswcl 13919 ccatval1lsw 13937 lswccatn0lsw 13944 swrdlsw 14028 pfxfvlsw 14056 repswlsw 14143 lswcshw 14176 lswco 14200 lsws2 14265 lsws3 14266 lsws4 14267 wrdl2exs2 14307 swrd2lsw 14313 psgnunilem5 18621 wlkonwlk1l 27444 wwlknlsw 27624 wwlksnext 27670 wwlksnredwwlkn 27672 wwlksnextproplem2 27688 clwlkclwwlklem2a1 27769 clwlkclwwlklem2a3 27771 clwlkclwwlklem2a4 27774 clwlkclwwlklem2 27777 clwwisshclwwslem 27791 clwwlknlbonbgr1 27816 clwwlkn2 27821 clwwlkel 27824 clwwlkf 27825 clwwlkwwlksb 27832 clwwlknonex2lem2 27886 2clwwlk2clwwlklem 28124 numclwwlk1lem2f1 28135 pfxlsw2ccat 30626 iwrdsplit 31645 signsvtn0 31840 signstfveq0 31847 lswn0 43603 |
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