Title
The Complexity Ecology of Parameters: An Illustration Using Bounded Max Leaf Number
Abstract
In the framework of parameterized complexity, exploring how one parameter affects the complexity of a different parameterized (or unparameterized problem) is of general interest. A well-developed example is the investigation of how the parameter treewidth influences the complexity of (other) graph problems. The reason why such investigations are of general interest is that real-world input distributions for computational problems often inherit structure from the natural computational processes that produce the problem instances (not necessarily in obvious, or well-understood ways). The max leaf number ml(G) of a connected graph G is the maximum number of leaves in a spanning tree for G. Exploring questions analogous to the well-studied case of treewidth, we can ask: how hard is it to solve 3-Coloring, Hamilton Path, Minimum Dominating Set, Minimum Bandwidth or many other problems, for graphs of bounded max leaf number? What optimization problems are W[1]-hard under this parameterization? We do two things: We describe much improved FPT algorithms for a large number of graph problems, for input graphs G for which ml(G)≤k, based on the polynomial-time extremal structure theory canonically associated to this parameter. We consider improved algorithms both from the point of view of kernelization bounds, and in terms of improved fixed-parameter tractable (FPT) runtimes O *(f(k)). The way that we obtain these concrete algorithmic results is general and systematic. We describe the approach, and raise programmatic questions.
Year
DOI
Venue
2009
10.1007/s00224-009-9167-9
Theory Comput. Syst.
Keywords
Field
DocType
improved fixed-parameter tractable,parameter treewidth,general interest,parameterized complexity,connected graph,large number,bounded max leaf number,max leaf number ml,graph problem,complexity ecology,maximum number,natural computing,polynomial time,spanning tree,optimization problem
Kernelization,Discrete mathematics,Combinatorics,Computational problem,Parameterized complexity,Tree-depth,Connected dominating set,Vertex cover,Spanning tree,Treewidth,Mathematics
Journal
Volume
Issue
ISSN
45
4
1432-4350
Citations 
PageRank 
References 
25
0.95
38
Authors
6
Name
Order
Citations
PageRank
Michael R. Fellows14138319.37
Daniel Lokshtanov21438110.05
Neeldhara Misra334131.42
Matthias Mnich425325.44
Frances A. Rosamond568434.52
Saket Saurabh62023179.50