Article ID Journal Published Year Pages File Type
5774797 Journal of Mathematical Analysis and Applications 2017 9 Pages PDF
Abstract
We present a beautiful but relatively unknown theorem that every differentiable function f:P→R, with P⊂R being closed, admits differentiable extension F:R→R. We present an elementary proof of this result based on a construction sketched in a hard-to-access 1923 paper [4] of V. Jarník. Using this construction, we also obtain an elegant version of Whitney extension theorem characterizing when such an f admits continuously differentiable extension.
Related Topics
Physical Sciences and Engineering Mathematics Analysis
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