OAI/GroupTheory/PolycyclicRecognition/Geometry/SegmentIncrementDerivative.lean
1 declarations, 0 contain sorry, 0 declared as axioms
Closed increment constraints pass to one-sided derivatives
- theorem
OAI.PolycyclicRecognition.derivative_mem_of_short_incrementsline 14Source documentation
Only positive short segments are needed to constrain the derivative. The derivative limit itself supplies all required convergence.
theorem derivative_mem_of_short_increments {W : Type*} [NormedAddCommGroup W] [NormedSpace ℝ W] (f : ℝ → W) (w : W) (hderiv : HasDerivAt f w 0) (S : Set W) (hS : IsClosed S) {T₀ : ℝ} (hT₀ : 0 < T₀) (hinc : ∀ t : ℝ, 0 < t → t < T₀ → t⁻¹ • (f t - f 0) ∈ S) : w ∈ S := by …