@incollection{eprints127, volume = {3705}, pages = {61--74}, series = {Lecture Notes in Computer Science}, title = {A General Name Binding Mechanism}, year = {2005}, note = {The final publication is available at www.springerlink.com.}, publisher = {Springer}, author = {Michele Boreale and Maria Grazia Buscemi and Ugo Montanari}, editor = {Rocco De Nicola and Davide Sangiorgi}, booktitle = {Proceedings of Symposium on Trustworthy Global Computing (TGC ?05)}, abstract = {We study fusion and binding mechanisms in name passing process calculi. To this purpose, we introduce the U-Calculus, a process calculus with no I/O polarities and a unique form of binding. The latter can be used both to control the scope of fusions and to handle new name generation. This is achieved by means of a simple form of typing: each bound name x is annotated with a set of exceptions, that is names that cannot be fused to x. The new calculus is proven to be more expressive than pi-calculus and Fusion calculus separately. In U-Calculus, the syntactic nesting of name binders has a semantic meaning, which cannot be overcome by the ordering of name extrusions at runtime. Thanks to this mixture of static and dynamic ordering of names, U-Calculus admits a form of labelled bisimulation which is a congruence. This property yields a substantial improvement with respect to previous proposals by the same authors aimed at unifying the above two languages. The additional expressiveness of U-Calculus is also explored by providing a uniform encoding of mixed guarded choice into the choice-free sub-calculus.}, url = {http://eprints.imtlucca.it/127/} }