Finite ordered fingerprint budgets
Lax342547.FingerprintCounts · concepts/Lax342547/FingerprintCounts.lean · lax-342547
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Lemma
Padding a fingerprint with absent entries injects all fingerprints of length at most L into words of length L over the raw alphabet with one extra symbol. Thus their number is at most (card U + 1)^L.
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| 1 | import Mathlib.Data.Fintype.BigOperators |
| 2 | import Mathlib.Data.List.Basic |
| 3 | |
| 4 | /-! |
| 5 | --- |
| 6 | title: Finite ordered fingerprint budgets |
| 7 | type: lemma |
| 8 | --- |
| 9 | Padding a fingerprint with absent entries injects all fingerprints of length at most L into words of length L over the raw alphabet with one extra symbol. Thus their number is at most (card U + 1)^L. |
| 10 | -/ |
| 11 | |
| 12 | namespace Lax342547.FingerprintCounts |
| 13 | |
| 14 | |
| 15 | |
| 16 | noncomputable def pad {U : Type} (L : ℕ) (l : List U) : List (Option U) := |
| 17 | l.map some ++ List.replicate (L-l.length) none |
| 18 | |
| 19 | axiom pad_recovers {U : Type} (L : ℕ) (l : List U) : (pad L l).filterMap id = l |
| 20 | |
| 21 | axiom pad_injective {U : Type} (L : ℕ) : Function.Injective (pad (U := U) L) |
| 22 | |
| 23 | axiom pad_length {U : Type} (L : ℕ) (l : List U) (hl : l.length ≤ L) : (pad L l).length = L |
| 24 | |
| 25 | axiom bounded_list_count {U : Type} [Fintype U] (T : Finset (List U)) (L : ℕ) |
| 26 | (hL : ∀ l ∈ T, l.length ≤ L) : T.card ≤ (Fintype.card U+1)^L |
| 27 | |
| 28 | end Lax342547.FingerprintCounts |
| 29 |
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