Matrices, graphs and equivalence relations

A suitable equivalence relation is introduced on the set of square matrices with entries of any kind. This allows us to associate to every equivalence class an infinite family of graphs and determine their topological properties. When a given square matrix is the multiplication table of a finite groupoid, some connections between algebraic properties of the groupoid and topological properties of these graphs are proved. Received: May 4, 1999 Published online: December 19, 2001