Córdoba's differentation theorem: revisited

Abstract

In this paper we prove an exponential covering lemma implying the three dimensional case of a well-known conjecture formulated by A. Zygmund circa 1935 and solved by A. Córdoba in 1978. Our approach avoids a subtle argument involving the power series of the exponential function.

arXiv admin note: text overlap with arXiv:1711.00803