Bigraphs with sharing and their algebra

Michele Sevegnani (University of Glasgow)

Wednesday 4th May, 2016 16:00-17:00 Maths 522


Bigraphical Reactive Systems (BRS) are a universal model of computation for the representation of interacting systems that evolve in both time and space. Bigraphs have been shown forming a category called symmetric partial monoidal category and their dynamic theory is defined in terms of rewriting and transition systems, which can be explained in a categorical setting by the notions of relative push-outs (RPOs) and idem push-outs (IPOs). A limitation of bigraphs is that the underlying model of location is a forest, which means there is no straightforward representation of locations that can overlap or intersect.

In this talk, I will introduce bigraphs with sharing, an extension of bigraphs which solves this problem by defining the model of location as a directed acyclic graph, thus allowing a natural representation of overlapping or intersecting locations. I will give a complete presentation of the extended theory, including a categorical semantics, algebraic properties, a normal form and several essential procedures for computation.


Michele Sevegnani is an EPSRC Doctoral Prize Research Fellow at the University of Glasgow, based in the School of Computing Science – profile: His research lies on the boundaries between mathematics (logics, category theory, probability) and computer science (event-based systems, formal methods, process calculi). His current work mainly focusses on the theory of bigraphs, a universal mathematical model for representing the spatial configuration of physical or virtual objects and their interaction capabilities. In particular, he uses bigraphs to reason about safety, reliability and predictability of location-aware, event-based, sensor systems, especially complex systems that are already deployed such as communication infrastructure for air traffic control, mixed-reality systems, wireless communication protocols and autonomous robotic systems.    

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