Software licenses, coverage, and subsumption

Abstract

Software licensing issues for a system design, instantiation, or configuration are often complex and difficult to evaluate, and mistakes can be costly. Automated assistance requires a formal representation of the significant features of the software licenses involved. We present results from an analysis directed toward a formal representation capable of covering an entire license. The key to such a representation is to identify the license's actions, and relate them to the actions for exclusive rights defined in law and to the actions defined in other licenses. Parameterizing each action by the object(s) acted on, the instrumental entities through which the action is performed, and similar contextual variables enables a subsumption relation among the actions. The resulting formalism is lightweight, flexible enough to support the scope of legal interpretations, and extensible to a wide range of software licenses. We discuss the application of our approach to the Lesser General Public License (LGPL) version 2.1.