Interface Simulation Distances Cerny, Pavol Chmelik, Martin Henzinger, Thomas A ; https://orcid.org/0000−0002−2985−7724 Radhakrishna, Arjun The classical (boolean) notion of refinement for behavioral interfaces of system components is the alternating refinement preorder. In this paper, we define a quantitative measure for interfaces, called interface simulation distance. It makes the alternating refinement preorder quantitative by, intu- itively, tolerating errors (while counting them) in the alternating simulation game. We show that the interface simulation distance satisfies the triangle inequality, that the distance between two interfaces does not increase under parallel composition with a third interface, and that the distance between two interfaces can be bounded from above and below by distances between abstractions of the two interfaces. We illustrate the framework, and the properties of the distances under composition of interfaces, with two case studies. EPTCS 2012 info:eu-repo/semantics/conferenceObject doc-type:conferenceObject text https://research-explorer.ista.ac.at/record/2916 Cerny P, Chmelik M, Henzinger TA, Radhakrishna A. Interface Simulation Distances. In: <i>Electronic Proceedings in Theoretical Computer Science</i>. Vol 96. EPTCS; 2012:29-42. doi:<a href="https://doi.org/10.4204/EPTCS.96.3">10.4204/EPTCS.96.3</a> eng info:eu-repo/semantics/altIdentifier/doi/10.4204/EPTCS.96.3 info:eu-repo/semantics/altIdentifier/arxiv/1210.2450 info:eu-repo/semantics/openAccess