Abstract
For an arbitrary infinite-dimensional Banach space đť”›, we construct examples of strongly-measurable đť”›-valued Pettis integrable functions whose indefinite Pettis integrals are nowhere weakly differentiable; thus, for these functions the Lebesgue Differentiation Theorem fails rather spectacularly. We also relate the degree of nondifferentia-bility of the indefinite Pettis integral to the cotype of đť”›, from which it follows that our examples are reasonably sharp.

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