Title
Packing and Covering Triangles in K 4-free Planar Graphs.
Abstract
We show that every K (4)-free planar graph with at most nu edge-disjoint triangles contains a set of at most edges whose removal makes the graph triangle-free. Moreover, equality is attained only when G is the edge-disjoint union of 5-wheels plus possibly some edges that are not in triangles. We also show that the same statement is true if instead of planar graphs we consider the class of graphs in which each edge belongs to at most two triangles. In contrast, it is known that for any c < 2 there are K (4)-free graphs with at most nu edge-disjoint triangles that need more than c nu edges to cover all triangles.
Year
DOI
Venue
2012
10.1007/s00373-011-1071-9
GRAPHS AND COMBINATORICS
Keywords
Field
DocType
Triangle packing and covering,Planar,Tuza's conjecture
Topology,Graph,Combinatorics,CPCTC,Planar,Nested triangles graph,Mathematics,Planar graph
Journal
Volume
Issue
ISSN
28
5
0911-0119
Citations 
PageRank 
References 
1
0.37
6
Authors
3
Name
Order
Citations
PageRank
Penny E. Haxell113016.64
Alexandr V. Kostochka268289.87
Stéphan Thomassé365166.03