This paper introduces the LINK system as an educational tool which can be used to visualize and experiment with discrete algorithms. An extended example demonstrates the flexibility of the system in the context of a fundamental graph algorithm: finding the strongly connected components of a directed graph.

Abstract not found

LINK is a set of C++ class libraries that supports applications in discrete mathematics. The libraries include a commandline interpreter and a graphical user interface that allow access to basic data structures such as Sets and Lists, and a graph hierarchy that includes undirected, directed, and "mixed" hypergraphs and graphs. A "mixed" graph may contain both directed and undirected edges. Many standard data structures including arrays, lists, heaps and binary search trees are within a Container hierarchy. Sets and Sequences are supported within a Collection hierarchy. The data structure hierarchies enable the user to experiment with competing data structure implementations, and with more complex and sophisticated data structures. If an algorithm has several possible choices of a data structure to be used, a single object can be created that is templated with the particular data structure desired. LINK also contains a set of graph generators, layout algorithms for hypergraphs and binar...

We survey computers systems which help to obtain and sometimes provide automatically conjectures and refutations in algebraic graph theory.

This paper will describe the basic architecture of the system and illustrate its flexibility with several examples. These descriptions will be accompanied by commentary on the associated design decisions, but will certainly not be exhaustive. The LINK manual fills in We would like to acknowledge the support of DIMACS and NSF grant CCR-9214487. DIMACS is a cooperative project of Rutgers University, Princeton University, AT&T Laboratories, Lucent Technologies/Bell Laboratories Innovations, and Bellcore. DIMACS is an NSF Science and Technology Center, funded under contract STC-91-19999; and also receives support from the New Jersey Commission on Science and Technology.

This document gives a preview of Link, a software system for graph theory and combinatorics which will be useful in both research and education. It should be

A percent-done progress indicator is a software tool that allows a user to monitor the progress that a software system has made toward responding to a command. Formal experiments have demonstrated that users prefer software systems that incorporate percentdone progress indicators over those that do not. Obviously, a system must be able to calculate (or at least estimate) the percentage of a computation that has been completed in order to support a percent-done progress indicator. This is generally straightforward for programs that make a xed number of linear passes over their input and then terminate (e.g., le transfer programs) . Most previous percent-done progress indicators have been limited to such programs. This paper presents a new technique called \dynamic bound evaluation " that allows percent-done progress indicators to be routinely incorporated into a wide range of programs that are driven by recursive algorithms that are not required to follow the \linear pass over data" p...