Bigraphs whose names have multiple locality

The previous definition of binding bigraphs is generalised so that local names may be located in more than one region, allowing more succinct and flexible presentation of bigraphical reactive systems. This report defines the generalisation, verifies that it retains relative pushouts, and introduces a new notion of bigraph extension; this admits a wider class of parametric reaction rules. Extension is shown to be well-behaved algebraically; one consequence is that —as in the original definition of bigraphs— discrete parameters are sufficient to generate all reactions. 1University of Cambridge, Computer Laboratory, JJ Thomson Avenue, Cambridge CB3 0FD, UK