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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 13927 | . . . 4 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (♯‘(𝑆 ++ 𝑇)) = ((♯‘𝑆) + (♯‘𝑇))) | |
2 | 1 | eqeq1d 2823 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((♯‘(𝑆 ++ 𝑇)) = 0 ↔ ((♯‘𝑆) + (♯‘𝑇)) = 0)) |
3 | ovex 7189 | . . . 4 ⊢ (𝑆 ++ 𝑇) ∈ V | |
4 | hasheq0 13725 | . . . 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 13883 | . . . . 5 ⊢ (𝑆 ∈ Word 𝐴 → (♯‘𝑆) ∈ ℕ0) | |
7 | nn0re 11907 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → (♯‘𝑆) ∈ ℝ) | |
8 | nn0ge0 11923 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → 0 ≤ (♯‘𝑆)) | |
9 | 7, 8 | jca 514 | . . . . 5 ⊢ ((♯‘𝑆) ∈ ℕ0 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
10 | 6, 9 | syl 17 | . . . 4 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
11 | lencl 13883 | . . . . 5 ⊢ (𝑇 ∈ Word 𝐵 → (♯‘𝑇) ∈ ℕ0) | |
12 | nn0re 11907 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → (♯‘𝑇) ∈ ℝ) | |
13 | nn0ge0 11923 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → 0 ≤ (♯‘𝑇)) | |
14 | 12, 13 | jca 514 | . . . . 5 ⊢ ((♯‘𝑇) ∈ ℕ0 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
15 | 11, 14 | syl 17 | . . . 4 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
16 | add20 11152 | . . . 4 ⊢ ((((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆)) ∧ ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) | |
17 | 10, 15, 16 | syl2an 597 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
18 | 2, 5, 17 | 3bitr3d 311 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
19 | hasheq0 13725 | . . 3 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) = 0 ↔ 𝑆 = ∅)) | |
20 | hasheq0 13725 | . . 3 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) = 0 ↔ 𝑇 = ∅)) | |
21 | 19, 20 | bi2anan9 637 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0) ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
22 | 18, 21 | bitrd 281 | 1 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1537 ∈ wcel 2114 Vcvv 3494 ∅c0 4291 class class class wbr 5066 ‘cfv 6355 (class class class)co 7156 ℝcr 10536 0cc0 10537 + caddc 10540 ≤ cle 10676 ℕ0cn0 11898 ♯chash 13691 Word cword 13862 ++ cconcat 13922 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2793 ax-rep 5190 ax-sep 5203 ax-nul 5210 ax-pow 5266 ax-pr 5330 ax-un 7461 ax-cnex 10593 ax-resscn 10594 ax-1cn 10595 ax-icn 10596 ax-addcl 10597 ax-addrcl 10598 ax-mulcl 10599 ax-mulrcl 10600 ax-mulcom 10601 ax-addass 10602 ax-mulass 10603 ax-distr 10604 ax-i2m1 10605 ax-1ne0 10606 ax-1rid 10607 ax-rnegex 10608 ax-rrecex 10609 ax-cnre 10610 ax-pre-lttri 10611 ax-pre-lttrn 10612 ax-pre-ltadd 10613 ax-pre-mulgt0 10614 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-mo 2622 df-eu 2654 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-nel 3124 df-ral 3143 df-rex 3144 df-reu 3145 df-rab 3147 df-v 3496 df-sbc 3773 df-csb 3884 df-dif 3939 df-un 3941 df-in 3943 df-ss 3952 df-pss 3954 df-nul 4292 df-if 4468 df-pw 4541 df-sn 4568 df-pr 4570 df-tp 4572 df-op 4574 df-uni 4839 df-int 4877 df-iun 4921 df-br 5067 df-opab 5129 df-mpt 5147 df-tr 5173 df-id 5460 df-eprel 5465 df-po 5474 df-so 5475 df-fr 5514 df-we 5516 df-xp 5561 df-rel 5562 df-cnv 5563 df-co 5564 df-dm 5565 df-rn 5566 df-res 5567 df-ima 5568 df-pred 6148 df-ord 6194 df-on 6195 df-lim 6196 df-suc 6197 df-iota 6314 df-fun 6357 df-fn 6358 df-f 6359 df-f1 6360 df-fo 6361 df-f1o 6362 df-fv 6363 df-riota 7114 df-ov 7159 df-oprab 7160 df-mpo 7161 df-om 7581 df-1st 7689 df-2nd 7690 df-wrecs 7947 df-recs 8008 df-rdg 8046 df-1o 8102 df-oadd 8106 df-er 8289 df-en 8510 df-dom 8511 df-sdom 8512 df-fin 8513 df-card 9368 df-pnf 10677 df-mnf 10678 df-xr 10679 df-ltxr 10680 df-le 10681 df-sub 10872 df-neg 10873 df-nn 11639 df-n0 11899 df-z 11983 df-uz 12245 df-fz 12894 df-fzo 13035 df-hash 13692 df-word 13863 df-concat 13923 |
This theorem is referenced by: clwwlkccat 27768 clwwlkwwlksb 27833 |
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