Borodin, Nielsen, and Rackoff gave a model of greedy-like algorithms for scheduling problems and Angelopoulos and Borodin extended their work to facility location and set cover problems. We generalize their notion to include other optimization problems, and apply the generalized framework to graph problems. Our goal is to define an ... more >>>

We introduce the notion of a plain basis for a co-clone in Post's lattice. Such a basis is a set of relations B such that every constraint C over a relation in the co-clone is logically equivalent to a conjunction of equalities and constraints over B and the same variables ... more >>>

We propose matchgate tensors as a natural and proper language
to develop Valiant's new theory of Holographic Algorithms.
We give a treatment of the central theorem in this theory---the Holant
Theorem---in terms of matchgate tensors.
Some generalizations are presented.

more >>>