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Mirrors > Home > MPE Home > Th. List > ccat0 | Structured version Visualization version GIF version |
Description: The concatenation of two words is empty iff the two words are empty. (Contributed by AV, 4-Mar-2022.) (Revised by JJ, 18-Jan-2024.) |
Ref | Expression |
---|---|
ccat0 | ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ccatlen 14523 | . . . 4 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (♯‘(𝑆 ++ 𝑇)) = ((♯‘𝑆) + (♯‘𝑇))) | |
2 | 1 | eqeq1d 2726 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((♯‘(𝑆 ++ 𝑇)) = 0 ↔ ((♯‘𝑆) + (♯‘𝑇)) = 0)) |
3 | ovex 7435 | . . . 4 ⊢ (𝑆 ++ 𝑇) ∈ V | |
4 | hasheq0 14321 | . . . 4 ⊢ ((𝑆 ++ 𝑇) ∈ V → ((♯‘(𝑆 ++ 𝑇)) = 0 ↔ (𝑆 ++ 𝑇) = ∅)) | |
5 | 3, 4 | mp1i 13 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((♯‘(𝑆 ++ 𝑇)) = 0 ↔ (𝑆 ++ 𝑇) = ∅)) |
6 | lencl 14481 | . . . . 5 ⊢ (𝑆 ∈ Word 𝐴 → (♯‘𝑆) ∈ ℕ0) | |
7 | nn0re 12479 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → (♯‘𝑆) ∈ ℝ) | |
8 | nn0ge0 12495 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → 0 ≤ (♯‘𝑆)) | |
9 | 7, 8 | jca 511 | . . . . 5 ⊢ ((♯‘𝑆) ∈ ℕ0 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
10 | 6, 9 | syl 17 | . . . 4 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
11 | lencl 14481 | . . . . 5 ⊢ (𝑇 ∈ Word 𝐵 → (♯‘𝑇) ∈ ℕ0) | |
12 | nn0re 12479 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → (♯‘𝑇) ∈ ℝ) | |
13 | nn0ge0 12495 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → 0 ≤ (♯‘𝑇)) | |
14 | 12, 13 | jca 511 | . . . . 5 ⊢ ((♯‘𝑇) ∈ ℕ0 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
15 | 11, 14 | syl 17 | . . . 4 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
16 | add20 11724 | . . . 4 ⊢ ((((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆)) ∧ ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) | |
17 | 10, 15, 16 | syl2an 595 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
18 | 2, 5, 17 | 3bitr3d 309 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
19 | hasheq0 14321 | . . 3 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) = 0 ↔ 𝑆 = ∅)) | |
20 | hasheq0 14321 | . . 3 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) = 0 ↔ 𝑇 = ∅)) | |
21 | 19, 20 | bi2anan9 636 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0) ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
22 | 18, 21 | bitrd 279 | 1 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 = wceq 1533 ∈ wcel 2098 Vcvv 3466 ∅c0 4315 class class class wbr 5139 ‘cfv 6534 (class class class)co 7402 ℝcr 11106 0cc0 11107 + caddc 11110 ≤ cle 11247 ℕ0cn0 12470 ♯chash 14288 Word cword 14462 ++ cconcat 14518 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2163 ax-ext 2695 ax-rep 5276 ax-sep 5290 ax-nul 5297 ax-pow 5354 ax-pr 5418 ax-un 7719 ax-cnex 11163 ax-resscn 11164 ax-1cn 11165 ax-icn 11166 ax-addcl 11167 ax-addrcl 11168 ax-mulcl 11169 ax-mulrcl 11170 ax-mulcom 11171 ax-addass 11172 ax-mulass 11173 ax-distr 11174 ax-i2m1 11175 ax-1ne0 11176 ax-1rid 11177 ax-rnegex 11178 ax-rrecex 11179 ax-cnre 11180 ax-pre-lttri 11181 ax-pre-lttrn 11182 ax-pre-ltadd 11183 ax-pre-mulgt0 11184 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2526 df-eu 2555 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-ne 2933 df-nel 3039 df-ral 3054 df-rex 3063 df-reu 3369 df-rab 3425 df-v 3468 df-sbc 3771 df-csb 3887 df-dif 3944 df-un 3946 df-in 3948 df-ss 3958 df-pss 3960 df-nul 4316 df-if 4522 df-pw 4597 df-sn 4622 df-pr 4624 df-op 4628 df-uni 4901 df-int 4942 df-iun 4990 df-br 5140 df-opab 5202 df-mpt 5223 df-tr 5257 df-id 5565 df-eprel 5571 df-po 5579 df-so 5580 df-fr 5622 df-we 5624 df-xp 5673 df-rel 5674 df-cnv 5675 df-co 5676 df-dm 5677 df-rn 5678 df-res 5679 df-ima 5680 df-pred 6291 df-ord 6358 df-on 6359 df-lim 6360 df-suc 6361 df-iota 6486 df-fun 6536 df-fn 6537 df-f 6538 df-f1 6539 df-fo 6540 df-f1o 6541 df-fv 6542 df-riota 7358 df-ov 7405 df-oprab 7406 df-mpo 7407 df-om 7850 df-1st 7969 df-2nd 7970 df-frecs 8262 df-wrecs 8293 df-recs 8367 df-rdg 8406 df-1o 8462 df-er 8700 df-en 8937 df-dom 8938 df-sdom 8939 df-fin 8940 df-card 9931 df-pnf 11248 df-mnf 11249 df-xr 11250 df-ltxr 11251 df-le 11252 df-sub 11444 df-neg 11445 df-nn 12211 df-n0 12471 df-z 12557 df-uz 12821 df-fz 13483 df-fzo 13626 df-hash 14289 df-word 14463 df-concat 14519 |
This theorem is referenced by: clwwlkccat 29715 clwwlkwwlksb 29779 |
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