347 search results - page 12 / 70 » Schaefer's theorem for graphs |
EJC
2008
14 years 9 months ago
2008
Abstract. We prove a general theorem on semigroup functions that implies characterizations of graph partition functions in terms of the positive semidefiniteness (`reflection posit...
SIAMCO
2000
14 years 9 months ago
2000
Given a nonlinear function h separating a convex and a concave function, we provide various conditions under which there exists an affine separating function whose graph is somewhe...
ALGORITHMICA
2011
14 years 4 months ago
2011
We show that computing the crossing number and the odd crossing number of a graph with a given rotation system is NP-complete. As a consequence we can show that many of the well-k...
MLQ
1998
14 years 9 months ago
1998
We examine a number of results of infinite combinatorics using the techniques of reverse mathematics. Our results are inspired by similar results in recursive combinatorics. Theor...
DAM
2002
14 years 9 months ago
2002
A graph is said to be uniquely list colorable, if it admits a list assignment which induces a unique list coloring. We study uniquely list colorable graphs with a restriction on t...