As I know that the .net-core can run UWP, can we build or write UWP with Core? I\'ve read the https://msdn.microsoft.com/en-us/magazine/mt694084.aspx
UWP apps will be able to use libraries you have created in .net core as long as you target the .netstandard1.6 (or higher) framework moniker.
UWP is only for the windows ecosystem.
See this article.