OAI/GroupTheory/PolycyclicRecognition/Analysis/SequenceScaleExtraction.lean
2 declarations, 0 contain sorry, 0 declared as axioms
Cofinal, strictly increasing scales with one fixed finite mode
- theorem
OAI.PolycyclicRecognition.exists_strictMono_scale_subsequenceline 14Source documentation
A divergent real scale can be made strictly increasing and at least one by restricting the original sequence.
theorem exists_strictMono_scale_subsequence (scale : ℕ → ℝ) (hs : Tendsto scale atTop atTop) : ∃ u : ℕ → ℕ, StrictMono u ∧ StrictMono (scale ∘ u) ∧ ∀ n, 1 ≤ scale (u n) := by … - theorem
OAI.PolycyclicRecognition.exists_constant_mode_strict_scaleline 32Source documentation
Fix a finite mode first, then make the real scales strictly increasing. This applies in particular to the finite family of word-basis selections.
theorem exists_constant_mode_strict_scale {I : Type*} [Finite I] (mode : ℕ → I) (scale : ℕ → ℝ) (hs : Tendsto scale atTop atTop) : ∃ (i : I) (u : ℕ → ℕ), StrictMono u ∧ StrictMono (scale ∘ u) ∧ (∀ n, 1 ≤ scale (u n)) ∧ ∀ n, mode (u n) = i := by …