On Three Alternative Characterizations of Combined Traces

TL;DR

This paper explores three equivalent ways to characterize combined traces (comtraces), generalizing Mazurkiewicz traces, by establishing representation theorems linking comtrace quotient monoids, dependency graphs, and stratified order structures.

Contribution

It introduces a new class of labeled stratified order structures that precisely captures comtraces and proves their equivalence with existing representations.

Findings

Comtraces are characterized by three equivalent representations.

The paper establishes representation theorems linking different comtrace models.

It extends previous work by providing a new structural characterization.

Abstract

The combined trace (i.e., comtrace) notion was introduced by Janicki and Koutny in 1995 as a generalization of the Mazurkiewicz trace notion. Comtraces are congruence classes of step sequences, where the congruence relation is defined from two relations simultaneity and serializability on events. They also showed that comtraces correspond to some class of labeled stratified order structures, but left open the question of what class of labeled stratified orders represents comtraces. In this work, we proposed a class of labeled stratified order structures that captures exactly the comtrace notion. Our main technical contributions are representation theorems showing that comtrace quotient monoid, combined dependency graph (Kleijn and Koutny 2008) and our labeled stratified order structure characterization are three different and yet equivalent ways to represent comtraces. This paper is a revised and expanded version of L\^e (in Proceedings of PETRI NETS 2010, LNCS 6128, pp. 104-124).