Decomposition of Sparse Graphs into Forests and a Graph with Bounded Degree

Series
Combinatorics Seminar
Time
Friday, November 4, 2011 - 3:05pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Prof. Douglas B. West – University of Illinois
Organizer
Xingxing Yu
Say that a graph with maximum degree at most $d$ is {\it $d$-bounded}.  For$d>k$, we prove a sharp sparseness condition for decomposition into $k$ forestsand a $d$-bounded graph.  The condition holds for every graph with fractionalarboricity at most $k+\FR d{k+d+1}$.  For $k=1$, it also implies that everygraph with maximum average degree less than $2+\FR{2d}{d+2}$ decomposes intoone forest and a $d$-bounded graph, which contains several earlier results onplanar graphs.