Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5774473 | Journal of Mathematical Analysis and Applications | 2017 | 7 Pages |
Abstract
Let p:RâR be a given function, and let Ap be the set of smooth functions f such that f(p(â
)+c) is smooth for any câR. We show that if p is not smooth, then either every element of Ap is constant, or there is a nonzero constant d such that Ap is equal to the set of smooth functions of periodicity d.
Keywords
Related Topics
Physical Sciences and Engineering
Mathematics
Analysis
Authors
Yongjie Shi, Chengjie Yu,