2024-03-28T22:19:41Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/696832022-11-17T02:08:08Zhdl_2115_45007hdl_2115_116EVOLUTION EQUATIONS WITH ALMOST PERIODIC INITIAL DATAGiga, Yoshikazu410It is rather clear that the solution is periodic if it is initially eriodic provided that the evolution equation under study is well-posed and ranslation invariant. It is less obvious to see that almost periodicity is reserved under slightly stronger assumptions. We are interested in evolution f the frequency set when initial data is almost periodic. We consider such problem for the Navier-Stokes equations and other evolution equations. typical result is that an additive group generated by frequency set called odule is contained in the module of initial data. We propose a method mbedding almost periodic problems to periodic problems which yields such result.Department of Mathematics, Hokkaido UniversityDepartmental Bulletin Paperapplication/pdfhttp://hdl.handle.net/2115/69683info:doi/10.14943/84024https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/69683/1/pre874.pdfHokkaido University Preprint Series in Mathematics8741142007engpublisher