Dear Srinivas, I have done some work along the lines that you mention. An abstract of one paper is appended below, and a citation to a second. I could send you copies if you like. There is also some work on sheaf theoretic semantics of digital circuits in preparation (with Victoria Stavridou and others) but not yet finished. I'd love a copy of your dissertation. Cheers, Joseph 00000000000000000000000000000000000000000000000000000000000000000000000000000 Semantics of Concurrent Interacting Objects using Sheaf Theory Joseph A. Goguen Sheaf theory was developed in mathematics to study relationships between local and global phenomena in analysis and geometry. This talk uses sheaf theory to explicate phenomena in concurrent systems, including object, active object, inheritance, deadlock, real time interaction, and security. This approach can then be applied to give semantics for object oriented languages and systems. 00000000000000000000000000000000000000000000000000000000000000000000000000000 @incollection(ehrich-goguen-sernadas91, title = "A Categorical Theory of Objects as Observed Processes", author = "Hans-Dieter Ehrich and Joseph Goguen and Amilcar Sernadas", booktitle = "Proceedings, {REX/FOOL} Workshop on Foundations of Object Oriented Languages", publisher = "Springer", year = 1991, editors = "J.W. deBakker and Gregorz Rozenberg", pages = "to appear", note = "Lecture Notes in Computer Science")