A function f of a graph is called a complete graph invariant if two given graphs G and H are isomorphic exactly when f(G) = f(H). If additionally, f(G) is a graph isomorphic to G, then f is called a canonical form for graphs. Gurevich [Gur97] proves that any polynomial-time computable complete invariant can be transformed into a polynomial-time computable canonical form. We extend this equivale...

This work presents an algorithm for the computation of canonical forms of linear codes over arbitrary finite chain rings under the action of the linear isometry group. It is a generalization of a previous work by the author on the canonization of linear codes over finite fields. The algorithm is based on the ideas of partition refinements and it will compute the automorphism group of the code a...

We present logspace algorithms for the canonical labeling problem and the representation problem of Helly circular-arc (HCA) graphs. The first step is a reduction to canonical labeling and representation of interval intersection matrices. In a second step, the Δ trees employed in McConnell’s linear time representation algorithm for interval matrices are adapted to the logspace setting and endow...