@InProceedings{GridWagner_ISAAC2006,
AUTHOR = {Erik D. Demaine and MohammadTaghi Hajiaghayi and
Ken-ichi Kawarabayashi},
TITLE = {Algorithmic Graph Minor Theory: Improved Grid Minor Bounds
and {Wagner}'s Contraction},
BOOKTITLE = {Proceedings of the 17th Annual International Symposium on
Algorithms and Computation (ISAAC 2006)},
bookurl = {http://www.isical.ac.in/~isaac06},
VOLUME = 4288,
SERIES = {Lecture Notes in Computer Science},
seriesurl = {http://www.springer.de/comp/lncs/},
ADDRESS = {Calcutta, India},
MONTH = {December 18--20},
YEAR = 2006,
PAGES = {3--15},
papers = {GridWagner_Algorithmica},
copyright = {The paper is \copyright Springer-Verlag.},
award = {Awarded Best Paper.
Invited to special issue of \emph{Algorithmica}.},
doi = {https://dx.doi.org/10.1007/11940128_3},
dblp = {https://dblp.org/rec/conf/isaac/DemaineHK06},
comments = {This paper is also available from <A HREF="http://dx.doi.org/10.1007/11940128_3">SpringerLink</A>.},
}
First, we obtain the only known polynomial min-max relation for graphs that do not exclude any fixed minor, namely, map graphs and power graphs. Second, we obtain explicit (and improved) bounds on the min-max relation for an important class of graphs excluding a minor, namely, K3,k-minor-free graphs, using new techniques that do not rely on Graph Minor Theory. These two avenues lead to faster fixed-parameter algorithms for two families of graph problems, called minor-bidimensional and contraction-bidimensional parameters. Third, we disprove a variation of Wagner's Conjecture for the case of graph contractions in general graphs, and in a sense characterize which graphs satisfy the variation. This result demonstrates the limitations of a general theory of algorithms for the family of contraction-closed problems (which includes, for example, the celebrated dominating-set problem). If this conjecture had been true, we would have had an extremely powerful tool for proving the existence of efficient algorithms for any contraction-closed problem, like we do for minor-closed problems via Graph Minor Theory.