24 research outputs found
Between quantum logic and concurrency
We start from two closure operators defined on the elements of a special kind
of partially ordered sets, called causal nets. Causal nets are used to model
histories of concurrent processes, recording occurrences of local states and of
events. If every maximal chain (line) of such a partially ordered set meets
every maximal antichain (cut), then the two closure operators coincide, and
generate a complete orthomodular lattice. In this paper we recall that, for any
closed set in this lattice, every line meets either it or its orthocomplement
in the lattice, and show that to any line, a two-valued state on the lattice
can be associated. Starting from this result, we delineate a logical language
whose formulas are interpreted over closed sets of a causal net, where every
line induces an assignment of truth values to formulas. The resulting logic is
non-classical; we show that maximal antichains in a causal net are associated
to Boolean (hence "classical") substructures of the overall quantum logic.Comment: In Proceedings QPL 2012, arXiv:1407.842
Application and Theory of Petri Nets33rd International Conference, PETRI NETS 2012, Hamburg, Germany, June 25-29, 2012. Proceedings /
XI, 419p.online resource
Non-Interference Notions Based on Reveals and Excludes Relations for Petri Nets
Abstract. In distributed systems, it is often important that a user is not able to infer if a given action has been performed by another component, while still being able to interact with that component. This kind of problems has been studied with the help of a notion of "interference" in formal models of concurrent systems (e.g. CCS, Petri nets). Here, we propose several new notions of interference for ordinary Petri nets, study some of their properties, and compare them with notions already proposed in the literature. Our new notions rely on the unfolding of Petri nets, and on an adaptation of the "reveals" relation for ordinary Petri nets, previously defined on occurrence nets, and on a new relation, called "excludes", here introduced for detecting negative information flow
Logic and algebra in unfolded Petri nets: on a duality between concurrency and causal dependence
An orthogonality space is a set endowed with a symmetric and irreflexive binary re- lation (an orthogonality relation). In a partially ordered set modelling a concurrent process, two such binary relations can be defined: a causal dependence relation and a concurrency relation, and two distinct orthogonality spaces are consequently obtained. When the condition of N-density holds on both these orthogonality spaces, we study the orthomodular poset formed by closed sets defined according to Dacey. We show that the condition originally imposed by Dacey on the or- thogonality spaces for obtaining an orthomodular poset from his closed sets is in fact equivalent to N-density. The requirement of N-density was as well fundamental in a previous work on or- thogonality spaces with the concurrency relation. Starting from a partially ordered set modelling a concurrent process, we obtain dual results for orthogonality spaces with the causal dependence relation in respect to orthogonality spaces with the concurrency relation.JRC.E.2-Technology Innovation in Securit