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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 6677 | . 2 ⊢ (𝑊‘((♯‘𝑊) − 1)) ∈ V | |
3 | id 22 | . . . 4 ⊢ (𝑤 = 𝑊 → 𝑤 = 𝑊) | |
4 | fveq2 6664 | . . . . 5 ⊢ (𝑤 = 𝑊 → (♯‘𝑤) = (♯‘𝑊)) | |
5 | 4 | oveq1d 7165 | . . . 4 ⊢ (𝑤 = 𝑊 → ((♯‘𝑤) − 1) = ((♯‘𝑊) − 1)) |
6 | 3, 5 | fveq12d 6671 | . . 3 ⊢ (𝑤 = 𝑊 → (𝑤‘((♯‘𝑤) − 1)) = (𝑊‘((♯‘𝑊) − 1))) |
7 | df-lsw 13909 | . . 3 ⊢ lastS = (𝑤 ∈ V ↦ (𝑤‘((♯‘𝑤) − 1))) | |
8 | 6, 7 | fvmptg 6760 | . 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 6349 (class class class)co 7150 1c1 10532 − cmin 10864 ♯chash 13684 lastSclsw 13908 |
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 5195 ax-nul 5202 ax-pr 5321 |
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 4561 df-pr 4563 df-op 4567 df-uni 4832 df-br 5059 df-opab 5121 df-mpt 5139 df-id 5454 df-xp 5555 df-rel 5556 df-cnv 5557 df-co 5558 df-dm 5559 df-iota 6308 df-fun 6351 df-fv 6357 df-ov 7153 df-lsw 13909 |
This theorem is referenced by: lsw0 13911 lsw1 13913 lswcl 13914 ccatval1lsw 13932 lswccatn0lsw 13939 swrdlsw 14023 pfxfvlsw 14051 repswlsw 14138 lswcshw 14171 lswco 14195 lsws2 14260 lsws3 14261 lsws4 14262 wrdl2exs2 14302 swrd2lsw 14308 psgnunilem5 18616 wlkonwlk1l 27439 wwlknlsw 27619 wwlksnext 27665 wwlksnredwwlkn 27667 wwlksnextproplem2 27683 clwlkclwwlklem2a1 27764 clwlkclwwlklem2a3 27766 clwlkclwwlklem2a4 27769 clwlkclwwlklem2 27772 clwwisshclwwslem 27786 clwwlknlbonbgr1 27811 clwwlkn2 27816 clwwlkel 27819 clwwlkf 27820 clwwlkwwlksb 27827 clwwlknonex2lem2 27881 2clwwlk2clwwlklem 28119 numclwwlk1lem2f1 28130 pfxlsw2ccat 30621 iwrdsplit 31640 signsvtn0 31835 signstfveq0 31842 lswn0 43598 |
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