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Theorem cshfn 14213
 Description: Perform a cyclical shift for a function over a half-open range of nonnegative integers. (Contributed by AV, 20-May-2018.) (Revised by AV, 17-Nov-2018.) (Revised by AV, 4-Nov-2022.)
Assertion
Ref Expression
cshfn ((𝑊 ∈ {𝑓 ∣ ∃𝑙 ∈ ℕ0 𝑓 Fn (0..^𝑙)} ∧ 𝑁 ∈ ℤ) → (𝑊 cyclShift 𝑁) = if(𝑊 = ∅, ∅, ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊))))))
Distinct variable group:   𝑓,𝑙
Allowed substitution hints:   𝑁(𝑓,𝑙)   𝑊(𝑓,𝑙)

Proof of Theorem cshfn
Dummy variables 𝑛 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 eqeq1 2763 . . . 4 (𝑤 = 𝑊 → (𝑤 = ∅ ↔ 𝑊 = ∅))
21adantr 484 . . 3 ((𝑤 = 𝑊𝑛 = 𝑁) → (𝑤 = ∅ ↔ 𝑊 = ∅))
3 simpl 486 . . . . 5 ((𝑤 = 𝑊𝑛 = 𝑁) → 𝑤 = 𝑊)
4 simpr 488 . . . . . . 7 ((𝑤 = 𝑊𝑛 = 𝑁) → 𝑛 = 𝑁)
5 fveq2 6664 . . . . . . . 8 (𝑤 = 𝑊 → (♯‘𝑤) = (♯‘𝑊))
65adantr 484 . . . . . . 7 ((𝑤 = 𝑊𝑛 = 𝑁) → (♯‘𝑤) = (♯‘𝑊))
74, 6oveq12d 7175 . . . . . 6 ((𝑤 = 𝑊𝑛 = 𝑁) → (𝑛 mod (♯‘𝑤)) = (𝑁 mod (♯‘𝑊)))
87, 6opeq12d 4775 . . . . 5 ((𝑤 = 𝑊𝑛 = 𝑁) → ⟨(𝑛 mod (♯‘𝑤)), (♯‘𝑤)⟩ = ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩)
93, 8oveq12d 7175 . . . 4 ((𝑤 = 𝑊𝑛 = 𝑁) → (𝑤 substr ⟨(𝑛 mod (♯‘𝑤)), (♯‘𝑤)⟩) = (𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩))
103, 7oveq12d 7175 . . . 4 ((𝑤 = 𝑊𝑛 = 𝑁) → (𝑤 prefix (𝑛 mod (♯‘𝑤))) = (𝑊 prefix (𝑁 mod (♯‘𝑊))))
119, 10oveq12d 7175 . . 3 ((𝑤 = 𝑊𝑛 = 𝑁) → ((𝑤 substr ⟨(𝑛 mod (♯‘𝑤)), (♯‘𝑤)⟩) ++ (𝑤 prefix (𝑛 mod (♯‘𝑤)))) = ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊)))))
122, 11ifbieq2d 4450 . 2 ((𝑤 = 𝑊𝑛 = 𝑁) → if(𝑤 = ∅, ∅, ((𝑤 substr ⟨(𝑛 mod (♯‘𝑤)), (♯‘𝑤)⟩) ++ (𝑤 prefix (𝑛 mod (♯‘𝑤))))) = if(𝑊 = ∅, ∅, ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊))))))
13 df-csh 14212 . 2 cyclShift = (𝑤 ∈ {𝑓 ∣ ∃𝑙 ∈ ℕ0 𝑓 Fn (0..^𝑙)}, 𝑛 ∈ ℤ ↦ if(𝑤 = ∅, ∅, ((𝑤 substr ⟨(𝑛 mod (♯‘𝑤)), (♯‘𝑤)⟩) ++ (𝑤 prefix (𝑛 mod (♯‘𝑤))))))
14 0ex 5182 . . 3 ∅ ∈ V
15 ovex 7190 . . 3 ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊)))) ∈ V
1614, 15ifex 4474 . 2 if(𝑊 = ∅, ∅, ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊))))) ∈ V
1712, 13, 16ovmpoa 7307 1 ((𝑊 ∈ {𝑓 ∣ ∃𝑙 ∈ ℕ0 𝑓 Fn (0..^𝑙)} ∧ 𝑁 ∈ ℤ) → (𝑊 cyclShift 𝑁) = if(𝑊 = ∅, ∅, ((𝑊 substr ⟨(𝑁 mod (♯‘𝑊)), (♯‘𝑊)⟩) ++ (𝑊 prefix (𝑁 mod (♯‘𝑊))))))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 209   ∧ wa 399   = wceq 1539   ∈ wcel 2112  {cab 2736  ∃wrex 3072  ∅c0 4228  ifcif 4424  ⟨cop 4532   Fn wfn 6336  ‘cfv 6341  (class class class)co 7157  0cc0 10589  ℕ0cn0 11948  ℤcz 12034  ..^cfzo 13096   mod cmo 13300  ♯chash 13754   ++ cconcat 13983   substr csubstr 14063   prefix cpfx 14093   cyclShift ccsh 14211 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1912  ax-6 1971  ax-7 2016  ax-8 2114  ax-9 2122  ax-10 2143  ax-11 2159  ax-12 2176  ax-ext 2730  ax-sep 5174  ax-nul 5181  ax-pr 5303 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1087  df-tru 1542  df-fal 1552  df-ex 1783  df-nf 1787  df-sb 2071  df-mo 2558  df-eu 2589  df-clab 2737  df-cleq 2751  df-clel 2831  df-nfc 2902  df-ral 3076  df-rex 3077  df-rab 3080  df-v 3412  df-sbc 3700  df-dif 3864  df-un 3866  df-in 3868  df-ss 3878  df-nul 4229  df-if 4425  df-sn 4527  df-pr 4529  df-op 4533  df-uni 4803  df-br 5038  df-opab 5100  df-id 5435  df-xp 5535  df-rel 5536  df-cnv 5537  df-co 5538  df-dm 5539  df-iota 6300  df-fun 6343  df-fv 6349  df-ov 7160  df-oprab 7161  df-mpo 7162  df-csh 14212 This theorem is referenced by:  cshword  14214
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