Authors: Richard Beigel and David Eppstein.
Abstract: We consider worst case time bounds for NP-complete problems including 3-coloring, 3-edge-coloring, and 3-list-coloring. Our algorithms are based on a common generalization of these problems, called symbol-system satisfiability or, briefly, SSS. 3-SAT is equivalent to (2,3)-SSS while the other problems above are special cases of (3,2)-SSS; there is also a natural duality transformation from (a,b)-SSS to (b,a)-SSS. We give a fast algorithm for (3,2)-SSS and use it to improve the time bounds for solving the other problems listed above.