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TauCeti.Geometry.Lie.Exponential.Derivative.Log

Derivatives involving the local Lie logarithm #

This file records first-order interactions between the local logarithm, the exponential, and group multiplication.

Main result #

theorem hasDerivAt_mulInvariantLog_mulInvariantExp_smul_mul_mulInvariantExp_smul {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {G : Type u_3} [TopologicalSpace G] [ChartedSpace H G] [Group G] [FiniteDimensional ℝ E] [LieGroup I (↑⊤) G] [T2Space G] [BoundarylessManifold I G] (X Y : GroupLieAlgebra I G) :
HasDerivAt (fun (t : ℝ) => have this := mulInvariantLog (mulInvariantExp (t • X) * mulInvariantExp (t • Y)); this) ((have this := X; this) + have this := Y; this) 0

The local logarithm of the product of two exponential lines has initial derivative X + Y.