Basics, Notation and Data Structures

Abstract

In the example that we used to introduce the software and in all our other examples the fundamental objects are graphs, that is a set of objects and links connecting or relating those objects. Sometimes the links bear additional data, like a length or a capacity and sometimes they are directed. Often, graphs are introduced as sets of vertices, the objects, and sets of edges, the links, where an edge is either an ordered or unordered pair of vertices.We prefer to proceed a bit more formally. The following definition allows to distinguish different links between a single pair of objects. What we will define here as a graph is sometimes also called a multigraph.