Declarative models and language concepts for the coordination in parallel and distributed systems attract increasing attention because of their simplicity and expressiveness. In this paper, type specialization is proposed as a declarative, object-oriented programming and coordination model. A simple execution mechanism repeatedly specializes types of entities (variables) and thereby collects kn...

In the last decade there have been many results about special families of graphs whose number of perfect matchings is given by perfect or near perfect powers (N. Elkies et al., J. Algebraic Combin. 1 (1992), 111– 132; B.-Y. Yang, Ph.D. thesis, Department of Mathematics, MIT, Cambridge, MA, 1991; J. Propp, New Perspectives in Geometric Combinatorics, Cambridge University Press, 1999). In this pa...

In 1961, P.W. Kasteleyn enumerated the domino tilings of a 2n × 2n chessboard. His answer was always a square or double a square (we call such a number "squarish"), but he did not provide a combinatorial explanation for this. In the present thesis, we prove by mostly combinatorial arguments that the number of matchings of a large class of graphs with 4-fold rotational symmetry is squarish; our ...

Program and data specialization have always been studied separately, although they are both aimed at processing early computations. Program specialization encodes the result of early computations into a new program; while data specialization encodes the result of early computations into data structures. In this paper, we present an extension of the Tempo specializer, which performs both program...

Debates about urban growth and change often center on specialization. However, arguments linking specialization to metropolitan economic development contain diverse, and sometimes conflicting, claims. Is it better to be highly specialized or diversified? Does specialization refer to the absolute or relative scale of an activity in a region? Does specialization have static or evolutionary effect...

A case is made to wed research on serious leisure and recreation specialization. Before such a marriage can occur, the strengths and differences of the two perspectives must be examined. In this article, four important contributions of the recreation specialization are put forward that will further our understanding of serious leisure and intense forms of leisure. These are (1) there is diversi...

In temporal specialization, the database designer restricts the relationship between the valid t ime-stamp (recording when something is true in the reality being modeled) and the transaction t ime-stamp (recording when a fact is stored in the database). An example is a retroactive temporal event relation, where the event must have occurred before it was stored, i.e., the valid t ime-stamp is re...

Traditional offline program specialization relies on staging of a computation into two levels, static and dynamic. We present a generalization thereof where the static input data of one level is split up in a potentially unknown number of separate fragments. These fragments arrive in an unspecified order and are specialized as they arrive. Potential applications of the technique include separat...

A graph is a split graph if its vertices can be partitioned into a clique and a stable set. A graph is a k-split graph if its vertices can be partitioned into k sets, each of which induces a split graph. We show that the strong perfect graph conjecture is true for 2-split graphs and we design a polynomial algorithm to recognize a perfect 2-split graph.

The scratching of pen against paper signaled something at once mundane and momentous. “What is your name, your age, your residence?” asked Harvey Risk, a representative of the Southern Claims Commission. “My name is Mary Blackburn.... My age is about forty-fi ve years. My residence near Middlebrook,” the claimant responded. The commission awarded compensation for property losses during the Amer...