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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 14130 | . . . 4 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (♯‘(𝑆 ++ 𝑇)) = ((♯‘𝑆) + (♯‘𝑇))) | |
2 | 1 | eqeq1d 2739 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((♯‘(𝑆 ++ 𝑇)) = 0 ↔ ((♯‘𝑆) + (♯‘𝑇)) = 0)) |
3 | ovex 7246 | . . . 4 ⊢ (𝑆 ++ 𝑇) ∈ V | |
4 | hasheq0 13930 | . . . 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 14088 | . . . . 5 ⊢ (𝑆 ∈ Word 𝐴 → (♯‘𝑆) ∈ ℕ0) | |
7 | nn0re 12099 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → (♯‘𝑆) ∈ ℝ) | |
8 | nn0ge0 12115 | . . . . . 6 ⊢ ((♯‘𝑆) ∈ ℕ0 → 0 ≤ (♯‘𝑆)) | |
9 | 7, 8 | jca 515 | . . . . 5 ⊢ ((♯‘𝑆) ∈ ℕ0 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
10 | 6, 9 | syl 17 | . . . 4 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆))) |
11 | lencl 14088 | . . . . 5 ⊢ (𝑇 ∈ Word 𝐵 → (♯‘𝑇) ∈ ℕ0) | |
12 | nn0re 12099 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → (♯‘𝑇) ∈ ℝ) | |
13 | nn0ge0 12115 | . . . . . 6 ⊢ ((♯‘𝑇) ∈ ℕ0 → 0 ≤ (♯‘𝑇)) | |
14 | 12, 13 | jca 515 | . . . . 5 ⊢ ((♯‘𝑇) ∈ ℕ0 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
15 | 11, 14 | syl 17 | . . . 4 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) |
16 | add20 11344 | . . . 4 ⊢ ((((♯‘𝑆) ∈ ℝ ∧ 0 ≤ (♯‘𝑆)) ∧ ((♯‘𝑇) ∈ ℝ ∧ 0 ≤ (♯‘𝑇))) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) | |
17 | 10, 15, 16 | syl2an 599 | . . 3 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) + (♯‘𝑇)) = 0 ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
18 | 2, 5, 17 | 3bitr3d 312 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ ((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0))) |
19 | hasheq0 13930 | . . 3 ⊢ (𝑆 ∈ Word 𝐴 → ((♯‘𝑆) = 0 ↔ 𝑆 = ∅)) | |
20 | hasheq0 13930 | . . 3 ⊢ (𝑇 ∈ Word 𝐵 → ((♯‘𝑇) = 0 ↔ 𝑇 = ∅)) | |
21 | 19, 20 | bi2anan9 639 | . 2 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → (((♯‘𝑆) = 0 ∧ (♯‘𝑇) = 0) ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
22 | 18, 21 | bitrd 282 | 1 ⊢ ((𝑆 ∈ Word 𝐴 ∧ 𝑇 ∈ Word 𝐵) → ((𝑆 ++ 𝑇) = ∅ ↔ (𝑆 = ∅ ∧ 𝑇 = ∅))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 209 ∧ wa 399 = wceq 1543 ∈ wcel 2110 Vcvv 3408 ∅c0 4237 class class class wbr 5053 ‘cfv 6380 (class class class)co 7213 ℝcr 10728 0cc0 10729 + caddc 10732 ≤ cle 10868 ℕ0cn0 12090 ♯chash 13896 Word cword 14069 ++ cconcat 14125 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2016 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2708 ax-rep 5179 ax-sep 5192 ax-nul 5199 ax-pow 5258 ax-pr 5322 ax-un 7523 ax-cnex 10785 ax-resscn 10786 ax-1cn 10787 ax-icn 10788 ax-addcl 10789 ax-addrcl 10790 ax-mulcl 10791 ax-mulrcl 10792 ax-mulcom 10793 ax-addass 10794 ax-mulass 10795 ax-distr 10796 ax-i2m1 10797 ax-1ne0 10798 ax-1rid 10799 ax-rnegex 10800 ax-rrecex 10801 ax-cnre 10802 ax-pre-lttri 10803 ax-pre-lttrn 10804 ax-pre-ltadd 10805 ax-pre-mulgt0 10806 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2071 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2729 df-clel 2816 df-nfc 2886 df-ne 2941 df-nel 3047 df-ral 3066 df-rex 3067 df-reu 3068 df-rab 3070 df-v 3410 df-sbc 3695 df-csb 3812 df-dif 3869 df-un 3871 df-in 3873 df-ss 3883 df-pss 3885 df-nul 4238 df-if 4440 df-pw 4515 df-sn 4542 df-pr 4544 df-tp 4546 df-op 4548 df-uni 4820 df-int 4860 df-iun 4906 df-br 5054 df-opab 5116 df-mpt 5136 df-tr 5162 df-id 5455 df-eprel 5460 df-po 5468 df-so 5469 df-fr 5509 df-we 5511 df-xp 5557 df-rel 5558 df-cnv 5559 df-co 5560 df-dm 5561 df-rn 5562 df-res 5563 df-ima 5564 df-pred 6160 df-ord 6216 df-on 6217 df-lim 6218 df-suc 6219 df-iota 6338 df-fun 6382 df-fn 6383 df-f 6384 df-f1 6385 df-fo 6386 df-f1o 6387 df-fv 6388 df-riota 7170 df-ov 7216 df-oprab 7217 df-mpo 7218 df-om 7645 df-1st 7761 df-2nd 7762 df-wrecs 8047 df-recs 8108 df-rdg 8146 df-1o 8202 df-er 8391 df-en 8627 df-dom 8628 df-sdom 8629 df-fin 8630 df-card 9555 df-pnf 10869 df-mnf 10870 df-xr 10871 df-ltxr 10872 df-le 10873 df-sub 11064 df-neg 11065 df-nn 11831 df-n0 12091 df-z 12177 df-uz 12439 df-fz 13096 df-fzo 13239 df-hash 13897 df-word 14070 df-concat 14126 |
This theorem is referenced by: clwwlkccat 28073 clwwlkwwlksb 28137 |
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