An algorithm of Beyer and Hedetniemi for generating unlabeled rooted trees is extended to generate unlabeled free trees. Abstract An algorithm of Beyer and Hedetniemi for generating unlabeled rooted trees is extended to generate unlabeled free trees. “The Beyer-Hedetniemi technique is refined to produce only one member of each equivalence class of rooted trees under isomorphism of the underlyin...

The existing pure tableau technique for satisfiability checking BCTL* [7] begins by constructing all possible colours. Traditional tableaux begin with a single root node, and only construct formulae that are derived from that root. These rooted tableaux provide much better performance on most real world formulae, as they only need to construct a fraction of the possible nodes. We present a root...

We describe a new family of free resolutions for a monomial ideal I , generalizing Lyubeznik’s construction. These resolutions are cellular resolutions supported on the rooted complexes of the lcm-lattice of I . Our resolutions are minimal for the matroid ideal of a finite projective space.