OAI/GroupTheory/PolycyclicRecognition/Geometry/SegmentIncrementDerivative.lean

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1 declarations, 0 contain sorry, 0 declared as axioms

Closed increment constraints pass to one-sided derivatives

  1. theorem OAI.PolycyclicRecognition.derivative_mem_of_short_increments line 14

    Source 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
    …