OAI/GroupTheory/PolycyclicRecognition/Algebra/RescaledBasisChange.lean
2 declarations, 0 contain sorry, 0 declared as axioms
Exponential margins between two rescalings of the same basis
- theorem
OAI.PolycyclicRecognition.repr_change_exponentialRescaleBasisline 14Source documentation
Exact coordinate change between two exponential rescalings.
theorem repr_change_exponentialRescaleBasis (b : Basis J ℝ L) (s t : J → ℝ) (r : ℝ) (x : L) (j : J) : (exponentialRescaleBasis b s r).repr x j = (exponentialRescaleBasis b t r).repr x j * Real.exp (r * (t j - s j)) := by … - theorem
OAI.PolycyclicRecognition.norm_change_exponentialRescaleBasis_leline 29Source documentation
A common difference between the exponents gives an exponential gain or loss in the whole coordinate maximum norm.
theorem norm_change_exponentialRescaleBasis_le [Fintype J] (b : Basis J ℝ L) (s t : J → ℝ) {r α : ℝ} (hr : 0 ≤ r) (hgap : ∀ j, t j - s j ≤ α) (x : L) : ‖(exponentialRescaleBasis b s r).equivFun x‖ ≤ Real.exp (r * α) * ‖(exponentialRescaleBasis b t r).equivFun x‖ := by …