Physical Sciences and Mathematics Commons^™

Smooth Peano Functions For Perfect Subsets Of The Real Line, Krzysztof Ciesielski

Faculty & Staff Scholarship

In this paper we investigate for which closed subsets P of the real line R there exists a continuous map from P onto P 2 and, if such a function exists, how smooth can it be. We show that there exists an infinitely many times differentiable function f : R → R 2 which maps an unbounded perfect set P onto P 2 . At the same time, no continuously differentiable function f : R → R 2 can map a compact perfect set onto its square. Finally, we show that a disconnected compact perfect set P admits a continuous …