]> 2012-02-10T15:44:21-05:00 A Proof Markup Language for Semantic Web Services Web services propose that they provide the means for remote interoperable access of components and software systems. However,successful inter-operation between components that do anything more than the simplest information retrieval is dependent upon those components having a shared understanding of the results that have passed between them. In this paper, we address the issue of understanding and trusting results generated by web services. We introduce a proof markup language (PML) that provides an interlingua for capturing the information agents need to understand results and to justify why they should believe the results. We also introduce our Inference Web infrastructure that uses PML as the foundation for providing explanations of web services to end users. We additionally show how PML is critical for and provides the foundation for hybrid reasoning. Our contributions in this paper focus on technological foundations for capturing formal representations of term meaning and justification descriptions thereby facilitating trust and reuse of answers from web agents. techreport 2004 A Proof Markup Language for Semantic Web Services KSL-04-01 2004 Technical Report A Proof Markup Language for Semantic Web Services 2004 Year Title NO Process note Number Note Ksl tr id Knowledge Systems, AI Laboratory Institution Has year Has where published Has title Has publishing details Has identifier Has author Bibtype Paulo Pinheiro da Silva and Deborah L. McGuinness and Richard Fikes Author Abstract KSL Technical Report Publication Technical Report