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Mirrors > Home > MPE Home > Th. List > wrdnfi | Structured version Visualization version GIF version |
Description: If there is only a finite number of symbols, the number of words of a fixed length over these symbols is also finite. (Contributed by Alexander van der Vekens, 25-Mar-2018.) Remove unnecessary antecedent. (Revised by JJ, 18-Nov-2022.) |
Ref | Expression |
---|---|
wrdnfi | ⊢ (𝑉 ∈ Fin → {𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ Fin) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hashwrdn 14591 | . . . . 5 ⊢ ((𝑉 ∈ Fin ∧ 𝑁 ∈ ℕ0) → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) = ((♯‘𝑉)↑𝑁)) | |
2 | hashcl 14401 | . . . . . 6 ⊢ (𝑉 ∈ Fin → (♯‘𝑉) ∈ ℕ0) | |
3 | nn0expcl 14122 | . . . . . 6 ⊢ (((♯‘𝑉) ∈ ℕ0 ∧ 𝑁 ∈ ℕ0) → ((♯‘𝑉)↑𝑁) ∈ ℕ0) | |
4 | 2, 3 | sylan 580 | . . . . 5 ⊢ ((𝑉 ∈ Fin ∧ 𝑁 ∈ ℕ0) → ((♯‘𝑉)↑𝑁) ∈ ℕ0) |
5 | 1, 4 | eqeltrd 2841 | . . . 4 ⊢ ((𝑉 ∈ Fin ∧ 𝑁 ∈ ℕ0) → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0) |
6 | 5 | ex 412 | . . 3 ⊢ (𝑉 ∈ Fin → (𝑁 ∈ ℕ0 → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0)) |
7 | lencl 14577 | . . . . . . . . . 10 ⊢ (𝑤 ∈ Word 𝑉 → (♯‘𝑤) ∈ ℕ0) | |
8 | eleq1 2829 | . . . . . . . . . 10 ⊢ ((♯‘𝑤) = 𝑁 → ((♯‘𝑤) ∈ ℕ0 ↔ 𝑁 ∈ ℕ0)) | |
9 | 7, 8 | syl5ibcom 245 | . . . . . . . . 9 ⊢ (𝑤 ∈ Word 𝑉 → ((♯‘𝑤) = 𝑁 → 𝑁 ∈ ℕ0)) |
10 | 9 | con3rr3 155 | . . . . . . . 8 ⊢ (¬ 𝑁 ∈ ℕ0 → (𝑤 ∈ Word 𝑉 → ¬ (♯‘𝑤) = 𝑁)) |
11 | 10 | ralrimiv 3145 | . . . . . . 7 ⊢ (¬ 𝑁 ∈ ℕ0 → ∀𝑤 ∈ Word 𝑉 ¬ (♯‘𝑤) = 𝑁) |
12 | rabeq0 4397 | . . . . . . 7 ⊢ ({𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} = ∅ ↔ ∀𝑤 ∈ Word 𝑉 ¬ (♯‘𝑤) = 𝑁) | |
13 | 11, 12 | sylibr 234 | . . . . . 6 ⊢ (¬ 𝑁 ∈ ℕ0 → {𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} = ∅) |
14 | 13 | fveq2d 6918 | . . . . 5 ⊢ (¬ 𝑁 ∈ ℕ0 → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) = (♯‘∅)) |
15 | hash0 14412 | . . . . 5 ⊢ (♯‘∅) = 0 | |
16 | 14, 15 | eqtrdi 2793 | . . . 4 ⊢ (¬ 𝑁 ∈ ℕ0 → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) = 0) |
17 | 0nn0 12548 | . . . 4 ⊢ 0 ∈ ℕ0 | |
18 | 16, 17 | eqeltrdi 2849 | . . 3 ⊢ (¬ 𝑁 ∈ ℕ0 → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0) |
19 | 6, 18 | pm2.61d1 180 | . 2 ⊢ (𝑉 ∈ Fin → (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0) |
20 | wrdexg 14568 | . . 3 ⊢ (𝑉 ∈ Fin → Word 𝑉 ∈ V) | |
21 | rabexg 5346 | . . 3 ⊢ (Word 𝑉 ∈ V → {𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ V) | |
22 | hashclb 14403 | . . 3 ⊢ ({𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ V → ({𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ Fin ↔ (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0)) | |
23 | 20, 21, 22 | 3syl 18 | . 2 ⊢ (𝑉 ∈ Fin → ({𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ Fin ↔ (♯‘{𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁}) ∈ ℕ0)) |
24 | 19, 23 | mpbird 257 | 1 ⊢ (𝑉 ∈ Fin → {𝑤 ∈ Word 𝑉 ∣ (♯‘𝑤) = 𝑁} ∈ Fin) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1539 ∈ wcel 2108 ∀wral 3061 {crab 3436 Vcvv 3481 ∅c0 4342 ‘cfv 6569 (class class class)co 7438 Fincfn 8993 0cc0 11162 ℕ0cn0 12533 ↑cexp 14108 ♯chash 14375 Word cword 14558 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1794 ax-4 1808 ax-5 1910 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-10 2141 ax-11 2157 ax-12 2177 ax-ext 2708 ax-rep 5288 ax-sep 5305 ax-nul 5315 ax-pow 5374 ax-pr 5441 ax-un 7761 ax-cnex 11218 ax-resscn 11219 ax-1cn 11220 ax-icn 11221 ax-addcl 11222 ax-addrcl 11223 ax-mulcl 11224 ax-mulrcl 11225 ax-mulcom 11226 ax-addass 11227 ax-mulass 11228 ax-distr 11229 ax-i2m1 11230 ax-1ne0 11231 ax-1rid 11232 ax-rnegex 11233 ax-rrecex 11234 ax-cnre 11235 ax-pre-lttri 11236 ax-pre-lttrn 11237 ax-pre-ltadd 11238 ax-pre-mulgt0 11239 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3or 1088 df-3an 1089 df-tru 1542 df-fal 1552 df-ex 1779 df-nf 1783 df-sb 2065 df-mo 2540 df-eu 2569 df-clab 2715 df-cleq 2729 df-clel 2816 df-nfc 2892 df-ne 2941 df-nel 3047 df-ral 3062 df-rex 3071 df-reu 3381 df-rab 3437 df-v 3483 df-sbc 3795 df-csb 3912 df-dif 3969 df-un 3971 df-in 3973 df-ss 3983 df-pss 3986 df-nul 4343 df-if 4535 df-pw 4610 df-sn 4635 df-pr 4637 df-op 4641 df-uni 4916 df-int 4955 df-iun 5001 df-br 5152 df-opab 5214 df-mpt 5235 df-tr 5269 df-id 5587 df-eprel 5593 df-po 5601 df-so 5602 df-fr 5645 df-we 5647 df-xp 5699 df-rel 5700 df-cnv 5701 df-co 5702 df-dm 5703 df-rn 5704 df-res 5705 df-ima 5706 df-pred 6329 df-ord 6395 df-on 6396 df-lim 6397 df-suc 6398 df-iota 6522 df-fun 6571 df-fn 6572 df-f 6573 df-f1 6574 df-fo 6575 df-f1o 6576 df-fv 6577 df-riota 7395 df-ov 7441 df-oprab 7442 df-mpo 7443 df-om 7895 df-1st 8022 df-2nd 8023 df-frecs 8314 df-wrecs 8345 df-recs 8419 df-rdg 8458 df-1o 8514 df-oadd 8518 df-er 8753 df-map 8876 df-pm 8877 df-en 8994 df-dom 8995 df-sdom 8996 df-fin 8997 df-dju 9948 df-card 9986 df-pnf 11304 df-mnf 11305 df-xr 11306 df-ltxr 11307 df-le 11308 df-sub 11501 df-neg 11502 df-nn 12274 df-n0 12534 df-z 12621 df-uz 12886 df-fz 13554 df-fzo 13701 df-seq 14049 df-exp 14109 df-hash 14376 df-word 14559 |
This theorem is referenced by: wwlksnfi 29952 clwwlknfi 30090 upwrdfi 46869 |
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