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Mirrors > Home > MPE Home > Th. List > ccat1st1st | Structured version Visualization version GIF version |
Description: The first symbol of a word concatenated with its first symbol is the first symbol of the word. This theorem holds even if 𝑊 is the empty word. (Contributed by AV, 26-Mar-2022.) |
Ref | Expression |
---|---|
ccat1st1st | ⊢ (𝑊 ∈ Word 𝑉 → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hasheq0 13720 | . . . 4 ⊢ (𝑊 ∈ Word 𝑉 → ((♯‘𝑊) = 0 ↔ 𝑊 = ∅)) | |
2 | 1 | biimpa 480 | . . 3 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) = 0) → 𝑊 = ∅) |
3 | s1cli 13950 | . . . . . . 7 ⊢ 〈“∅”〉 ∈ Word V | |
4 | ccatlid 13931 | . . . . . . 7 ⊢ (〈“∅”〉 ∈ Word V → (∅ ++ 〈“∅”〉) = 〈“∅”〉) | |
5 | 3, 4 | ax-mp 5 | . . . . . 6 ⊢ (∅ ++ 〈“∅”〉) = 〈“∅”〉 |
6 | 5 | fveq1i 6646 | . . . . 5 ⊢ ((∅ ++ 〈“∅”〉)‘0) = (〈“∅”〉‘0) |
7 | 0ex 5175 | . . . . . 6 ⊢ ∅ ∈ V | |
8 | s1fv 13955 | . . . . . 6 ⊢ (∅ ∈ V → (〈“∅”〉‘0) = ∅) | |
9 | 7, 8 | ax-mp 5 | . . . . 5 ⊢ (〈“∅”〉‘0) = ∅ |
10 | 6, 9 | eqtri 2821 | . . . 4 ⊢ ((∅ ++ 〈“∅”〉)‘0) = ∅ |
11 | id 22 | . . . . . 6 ⊢ (𝑊 = ∅ → 𝑊 = ∅) | |
12 | fveq1 6644 | . . . . . . . 8 ⊢ (𝑊 = ∅ → (𝑊‘0) = (∅‘0)) | |
13 | 0fv 6684 | . . . . . . . 8 ⊢ (∅‘0) = ∅ | |
14 | 12, 13 | eqtrdi 2849 | . . . . . . 7 ⊢ (𝑊 = ∅ → (𝑊‘0) = ∅) |
15 | 14 | s1eqd 13946 | . . . . . 6 ⊢ (𝑊 = ∅ → 〈“(𝑊‘0)”〉 = 〈“∅”〉) |
16 | 11, 15 | oveq12d 7153 | . . . . 5 ⊢ (𝑊 = ∅ → (𝑊 ++ 〈“(𝑊‘0)”〉) = (∅ ++ 〈“∅”〉)) |
17 | 16 | fveq1d 6647 | . . . 4 ⊢ (𝑊 = ∅ → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = ((∅ ++ 〈“∅”〉)‘0)) |
18 | 10, 17, 14 | 3eqtr4a 2859 | . . 3 ⊢ (𝑊 = ∅ → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) |
19 | 2, 18 | syl 17 | . 2 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) = 0) → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) |
20 | 1 | necon3bid 3031 | . . . . . 6 ⊢ (𝑊 ∈ Word 𝑉 → ((♯‘𝑊) ≠ 0 ↔ 𝑊 ≠ ∅)) |
21 | 20 | biimpa 480 | . . . . 5 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) ≠ 0) → 𝑊 ≠ ∅) |
22 | lennncl 13877 | . . . . 5 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 𝑊 ≠ ∅) → (♯‘𝑊) ∈ ℕ) | |
23 | 21, 22 | syldan 594 | . . . 4 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) ≠ 0) → (♯‘𝑊) ∈ ℕ) |
24 | lbfzo0 13072 | . . . 4 ⊢ (0 ∈ (0..^(♯‘𝑊)) ↔ (♯‘𝑊) ∈ ℕ) | |
25 | 23, 24 | sylibr 237 | . . 3 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) ≠ 0) → 0 ∈ (0..^(♯‘𝑊))) |
26 | ccats1val1 13972 | . . 3 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 0 ∈ (0..^(♯‘𝑊))) → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) | |
27 | 25, 26 | syldan 594 | . 2 ⊢ ((𝑊 ∈ Word 𝑉 ∧ (♯‘𝑊) ≠ 0) → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) |
28 | 19, 27 | pm2.61dane 3074 | 1 ⊢ (𝑊 ∈ Word 𝑉 → ((𝑊 ++ 〈“(𝑊‘0)”〉)‘0) = (𝑊‘0)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 399 = wceq 1538 ∈ wcel 2111 ≠ wne 2987 Vcvv 3441 ∅c0 4243 ‘cfv 6324 (class class class)co 7135 0cc0 10526 ℕcn 11625 ..^cfzo 13028 ♯chash 13686 Word cword 13857 ++ cconcat 13913 〈“cs1 13940 |
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-rep 5154 ax-sep 5167 ax-nul 5174 ax-pow 5231 ax-pr 5295 ax-un 7441 ax-cnex 10582 ax-resscn 10583 ax-1cn 10584 ax-icn 10585 ax-addcl 10586 ax-addrcl 10587 ax-mulcl 10588 ax-mulrcl 10589 ax-mulcom 10590 ax-addass 10591 ax-mulass 10592 ax-distr 10593 ax-i2m1 10594 ax-1ne0 10595 ax-1rid 10596 ax-rnegex 10597 ax-rrecex 10598 ax-cnre 10599 ax-pre-lttri 10600 ax-pre-lttrn 10601 ax-pre-ltadd 10602 ax-pre-mulgt0 10603 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3or 1085 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-ne 2988 df-nel 3092 df-ral 3111 df-rex 3112 df-reu 3113 df-rab 3115 df-v 3443 df-sbc 3721 df-csb 3829 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-pss 3900 df-nul 4244 df-if 4426 df-pw 4499 df-sn 4526 df-pr 4528 df-tp 4530 df-op 4532 df-uni 4801 df-int 4839 df-iun 4883 df-br 5031 df-opab 5093 df-mpt 5111 df-tr 5137 df-id 5425 df-eprel 5430 df-po 5438 df-so 5439 df-fr 5478 df-we 5480 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-rn 5530 df-res 5531 df-ima 5532 df-pred 6116 df-ord 6162 df-on 6163 df-lim 6164 df-suc 6165 df-iota 6283 df-fun 6326 df-fn 6327 df-f 6328 df-f1 6329 df-fo 6330 df-f1o 6331 df-fv 6332 df-riota 7093 df-ov 7138 df-oprab 7139 df-mpo 7140 df-om 7561 df-1st 7671 df-2nd 7672 df-wrecs 7930 df-recs 7991 df-rdg 8029 df-1o 8085 df-oadd 8089 df-er 8272 df-en 8493 df-dom 8494 df-sdom 8495 df-fin 8496 df-card 9352 df-pnf 10666 df-mnf 10667 df-xr 10668 df-ltxr 10669 df-le 10670 df-sub 10861 df-neg 10862 df-nn 11626 df-n0 11886 df-z 11970 df-uz 12232 df-fz 12886 df-fzo 13029 df-hash 13687 df-word 13858 df-concat 13914 df-s1 13941 |
This theorem is referenced by: clwwlknonwwlknonb 27891 |
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