首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Classification of immersions of graphs into a plane
Authors:D A Permyakov
Institution:(1) Faculty of Mechanics and Mathematics, Moscow State University, Leninskie Gory, Moscow, 119899, Russia
Abstract:In 2005, R. Nikkuni calculated the Wu invariant for immersions of graphs into a plane considered up to a regular homotopy, i.e., for homotopies that are immersions. He showed that two immersions are regularly homotopic if and only if their Wu invariants coincide. In this paper a simple combinatorial construction for this invariant is described, a theorem similar to Ryo Nikkuni’s theorem is proved, and the fact that all values of the constructed combinatorial invariant can be implemented by immersions is also proved.
Keywords:
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号