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


Planar graphs without 4‐cycles adjacent to 3‐cycles are list vertex 2‐arborable
Authors:Oleg V Borodin  Anna O Ivanova
Institution:1. Institute of Mathematics Siberian Branch of the Russian Academy of Sciences Novosibirsk, 630090, Russia;2. Yakutsk State University Yakutsk, 677000, Russia
Abstract:It is known that not all planar graphs are 4‐choosable; neither all of them are vertex 2‐arborable. However, planar graphs without 4‐cycles and even those without 4‐cycles adjacent to 3‐cycles are known to be 4‐choosable. We extend this last result in terms of covering the vertices of a graph by induced subgraphs of variable degeneracy. In particular, we prove that every planar graph without 4‐cycles adjacent to 3‐cycles can be covered by two induced forests. © 2009 Wiley Periodicals, Inc. J Graph Theory 62, 234–240, 2009
Keywords:graph covering  induced subgraphs  list coloring  point arboricity
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