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**Models of Sharing Graphs** presents a sound mathematical basis for reasoning about models of computation involving shared resources, including graph rewriting systems, denotational semantics and concurrency theory. An algebraic approach, based on the language of category theory, is taken throughout this work, which enables the author to describe several aspects of the notion of sharing in a systematic way. In particular, a novel account of recursive computation created from cyclic sharing is developed using this framework. Front Matter....Pages I-XII Introduction....Pages 1-17 Sharing Graphs and Equational Presentation....Pages 19-38 Models of Acyclic Sharing Theory....Pages 39-56 Higher-Order Extension....Pages 57-63 Relating Models....Pages 65-70 Models of Cyclic Sharing Theory....Pages 71-81 Recursion from Cyclic Sharing....Pages 83-101 Action Calculi....Pages 103-113 Conclusion....Pages 115-116 Back Matter....Pages 117-134 Introduction Sharing Graphs and Equational Presentation Models of Acyclic Sharing Theroy Higher Order Extension Relating Models Models of Cyclic Sharing Theory Recursion from Cyclic Sharing Action Calculi Conclusion Proofs Bibliography Index.