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Specifying Interaction Categories
, 1997
"... We analyse two complementary methods for obtaining models of typed process calculi, in the form of interaction categories. These methods allow adding new features to previously captured notions of process and of type, respectively. By combining them, all familiar examples of interaction categories, ..."
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Cited by 11 (2 self)
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We analyse two complementary methods for obtaining models of typed process calculi, in the form of interaction categories. These methods allow adding new features to previously captured notions of process and of type, respectively. By combining them, all familiar examples of interaction categories, as well as some new ones, can be built starting from some simple familiar categories. Using the presented constructions, interaction categories can be analysed without fixing a set of axioms, merely in terms of the way in which they are specified  just like algebras are analysed in terms of equations and relations, independently on abstract characterisations of their varieties.
Quantum Computing: A new Paradigm and it's Type Theory
 Lecture given at the Quantum Computing Seminar, Lehrstuhl Prof. Beth, Universität
, 1996
"... To use quantum mechanical behavior for computing has been proposed by Feynman. Shor gave an algorithm for the quantum computer which raised a big stream of research. This was because Shor's algorithm did reduce the yet assumed exponential complexity of the security relevant factorization problem, to ..."
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Cited by 3 (0 self)
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To use quantum mechanical behavior for computing has been proposed by Feynman. Shor gave an algorithm for the quantum computer which raised a big stream of research. This was because Shor's algorithm did reduce the yet assumed exponential complexity of the security relevant factorization problem, to a quadratic complexity if quantum computed. In the paper a short introduction to quantum mechanics can be found in the appendix. With this material the operation of the quantum computer, and the ideas of quantum logic will be explained. The focus will be the argument that a connection of quantum logic and linear logic is the right type theory for quantum computing. These ideas are inspired by Vaughan Pratt's view that the intuitionistic formulas argue about states (i.e physical quantum states) and linear formulas argue about state transformations (i.e computation steps). 1 Introduction A calculus for programs on quantum computers is strongly missed. Here we present the material t...
Convenient Category of Processes and Simulations I: Modulo Strong Bisimilarity
, 1995
"... Deep categorical analyses of various aspects of concurrency have been developed, but a uniform categorical treatment of the very first concepts seems to be hindered by the fact that the existing representations of processes as bisimilarity classes do not provide a sufficient account of computational ..."
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Cited by 1 (1 self)
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Deep categorical analyses of various aspects of concurrency have been developed, but a uniform categorical treatment of the very first concepts seems to be hindered by the fact that the existing representations of processes as bisimilarity classes do not provide a sufficient account of computational morphisms. In the present paper, we describe a category of processes modulo strong bisimulations, with the bisimilarity preserving simulations as morphisms, and show that it is isomorphic to  and can be conveniently represented by  a subcategory of transition systems, with graph morphisms. The representative of each process and every morphism can effectively calculated, using coinduction (but with no reference to proper classes). The method is applicable to richer notions of a process as well, which are studied in the sequel. 1 Introduction A process is usually presented as some kind of a labelled graph. In fact, any directed graph with labelled edges and a distinguished initial node...
Formalizing Physical Security Procedures
"... Abstract. Although the problems of physical security emerged more than 10,000 years before the problems of computer security, no formal methods have been developed for them, and the solutions have been evolving slowly, mostly through social procedures. But as the traffic on physical and social netwo ..."
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Abstract. Although the problems of physical security emerged more than 10,000 years before the problems of computer security, no formal methods have been developed for them, and the solutions have been evolving slowly, mostly through social procedures. But as the traffic on physical and social networks is now increasingly expedited by computers, the problems of physical and social security are becoming technical problems. From various directions, many security researchers and practitioners have come to a realization that the areas such as transportation security, public and private space protection, or critical infrastructure defense, are in need of formalized engineering methodologies. Following this lead, we extended Protocol Derivation Logic (PDL) to Procedure Derivation Logic (still PDL). In contrast with a protocol, where some principals send and receive some messages, in a procedure they can also exchange and move some objects. For simplicity, in the present paper we actually focus on the security issues arising from traffic of objects, and leave the data flows, and the phenomena emerging from the interaction of data and objects, for future work. We illustrate our approach by applying it to a flawed airport security procedure described by Schneier.