EGG Graphical Editing of Graphs description
The EGG programs package proposes to offer an easy to use environment for drawing graphs

Graphs are mathematical objects wich require a graphical representation in order to understand their properties. The elements of a graph are vertices and edges, and can be represented by points respectivelly straight or curved lines.

Many of the graph theory problems, such as paths, planarity or coloring problems, are quite difficult to understand without this kind of representation.

At this moment there is a series of free or comercial graphical applications used for the representation and manipulation of complex graphical objects, but graph drawing needs specific interface and features.

The EGG programs package proposes to offer an easy to use environment for drawing graphs, directed or undirected, with relatively big dimensions, thousands of vertices and edges.

A number of graph theory specific concepts, some frequently used algorithms and characteristic data structures can be visualized during the investigation process or can be used for illustrating certain themes, presentations, lessons and lectures to pupils and students.

The EGG application offers standard editing features like adding and placing vertices, defining edges or arcs, with the possibility of editing and deleting them. Mechanisms of copy/paste type complete the set of direct edit features.

A series of information, like costs and/or labels associated to edges and vertices can be visualized in the program's graphical space. EGG offers and specific editing features like: transforming a subgraph of the current graph into a clique, stable set, star, path, cycle, complement or other known structures.

For a subgraph there can also be obtained a clone (perfect copy), a twin (a copy that keeps the connections with the complementary graph) and the collapse (replacement of the subgraph with a single vertex with the keeping of the adjacencies). Furthermore, EGG offers a process which random generates vertices and edges, obtaining some graphs samples.

The data structure used permits a large set of information retrievals like: the construction of adjacency and edges-vertices incidence matrices, vertices and edges search, the search for minimum length or cost paths, the generation of DFS or BFS tree, the detection of minimum or maximum spanning tree.