{ "id": "1906.03727", "version": "v1", "published": "2019-06-09T22:30:52.000Z", "updated": "2019-06-09T22:30:52.000Z", "title": "On pointwise convergence of Schrödinger means", "authors": [ "Evangelos Dimou", "Andreas Seeger" ], "categories": [ "math.CA", "math.AP" ], "abstract": "For functions in the Sobolev space $H^s$ and decreasing sequences $t_n\\to 0$ we examine convergence almost everywhere of the generalized Schr\\\"odinger means on the real line, given by \\[S^af(x,t_n)=\\exp( it_n (-\\partial_{xx})^{a/2})f(x);\\] here $a>0$, $a\\neq 1$. For decreasing convex sequences we obtain a simple characterization of convergence a.e. for all functions in $H^s$ when $0