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arXiv · 1505.05793

Differentiability and Poincaré-type inequalities in metric measure spaces

David Bate·Sean Li
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Abstract

We demonstrate the necessity of a Poincaré type inequality for those metric measure spaces that satisfy Cheeger's generalization of Rademacher's theorem for all Lipschitz functions taking values in a Banach space with the Radon-Nikodym property. This is done by showing the existence of a rich structure of curve fragments that connect near by points, similar in nature to Semmes's pencil of curves for the standard Poincaré inequality. Using techniques similar to Cheeger-Kleiner, we show that our conditions are also sufficient. We also develop another characterization of "RNP Lipschitz differentiability spaces" by connecting points by curves that form a rich structure of partial derivatives that were first discussed in work by the first author.

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David Bate, Sean Li. 2018-02-13. Differentiability and Poincaré-type inequalities in metric measure spaces. https://doi.org/10.1016/j.aim.2018.06.002

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