Workshop on Modelling of Objects, Components, and Agents, Aarhus, Denmark, August 27-28, 2001

This booklet contains the proceedings of the workshop Modelling of Objects, Components, and Agents (MOCA'01), August 27-28, 2001. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark and the "Theoretical Foundations of Computer Science" Group at the University of Hamburg, Germany. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop01

ParaPlan: A Tool for Parallel Reachability Analysis of Planar Polygonal Differential Inclusion Systems

Andrei Sandler, and Olga Tveretina, ‘ParaPlan: A Tool for Parallel Reachability Analysis of Planar Polygonal Differential Inclusion Systems’, in Patricia Bouyer, Andrea Orlandini and Pierluigi San Pietro, eds. Proceedings Eight International Symposium on Games, Automata, Logics and Formal Verification (GandALF 2017), Rome, Italy, 20-22 September 2017, Electronic Proceedings in Theoretical Computer Science, Vol. 256: 283-296, September 2017. © 2017 The Author(s). This work is licensed under the Creative Commons Attribution License CC BY 4.0 https://creativecommons.org/licenses/by/4.0/We present the ParaPlan tool which provides the reachability analysis of planar hybrid systems defined by differential inclusions (SPDI). It uses the parallelized and optimized version of the algorithm underlying the SPeeDI tool. The performance comparison demonstrates the speed-up of up to 83 times with respect to the sequential implementation on various benchmarks. Some of the benchmarks we used are randomly generated with the novel approach based on the partitioning of the plane with Voronoi diagrams

fixed point

The study of the dual complexity space, introduced by S. Romaguera and M. P. Schellekens [Quasi-metric properties of complexity spaces, Topol. Appl. 98 (1999), pp. 311-322], constitutes a part of the interdisciplinary research on Computer Science and Topology. The relevance of this theory is given by the fact that it allows one to apply fixed point techniques of denotational semantics to complexity analysis. Motivated by this fact and with the intention of obtaining a mixed framework valid for both disciplines, a new complexity space formed by partial functions was recently introduced and studied by S. Romaguera and O. Valero [On the structure of the space of complexity partial functions, Int. J. Comput. Math. 85 (2008), pp. 631-640]. An application of the complexity space of partial functions to model certain processes that arise, in a natural way, in symbolic computation was given in the aforementioned reference. In this paper, we enter more deeply into the relationship between semantics and complexity analysis of programs. We construct an extension of the complexity space of partial functions and show that it is, at the same time, an appropriate mathematical tool for the complexity analysis of algorithms and for the validation of recursive definitions of programs. As applications of our complexity framework, we show the correctness of the denotational specification of the factorial function and give an alternative formal proof of the asymptotic upper bound for the average case analysis of Quicksort.The first and the third authors acknowledge the support of the Spanish Ministry of Science and Innovation, and FEDER, grant MTM2009-12872-C02-01 (subprogram MTM), and the support of Generalitat Valenciana, grant ACOMP2009/005. The second author acknowledges the support of the Science Foundation Ireland, SFI Principal Investigator Grant 07/IN.1/I977.Romaguera Bonilla, S.; Schellekens, M.; Valero Sierra, Ó. (2011). The complexity space of partial functions: A connection between Complexity Analysis and Denotational Semantics. International Journal of Computer Mathematics. 88(9):1819-1829. https://doi.org/10.1080/00207161003631885S18191829889De Bakker, J. W., & de Vink, E. P. (1998). Denotational models for programming languages: applications of Banach’s Fixed Point Theorem. Topology and its Applications, 85(1-3), 35-52. doi:10.1016/s0166-8641(97)00140-5Emerson, E. A., & Jutla, C. S. (1999). The Complexity of Tree Automata and Logics of Programs. SIAM Journal on Computing, 29(1), 132-158. doi:10.1137/s0097539793304741Flajolet, P., & Golin, M. (1994). Mellin transforms and asymptotics. Acta Informatica, 31(7), 673-696. doi:10.1007/bf01177551García-Raffi, L. M., Romaguera, S., & Sánchez-Pérez, E. A. (2002). Sequence spaces and asymmetric norms in the theory of computational complexity. Mathematical and Computer Modelling, 36(1-2), 1-11. doi:10.1016/s0895-7177(02)00100-0García-Raffi, L. M., Romaguera, S., & Sánchez-Pérez, E. A. (2003). The supremum asymmetric norm on sequence algebras. Electronic Notes in Theoretical Computer Science, 74, 39-50. doi:10.1016/s1571-0661(04)80764-3García-Raffi, L. M., Romaguera, S., Sánchez-Pérez, E. A. and Valero, O. Normed Semialgebras: A Mathematical Model for the Complexity Analysis of Programs and Algorithms. Proceedings of The 7th World Multiconference on Systemics, Cybernetics and Informatics (SCI 2003), Orlando, Florida, USA. Edited by: Callaos, N., Di Sciullo, A. M., Ohta, T. and Liu, T.K. Vol. II, pp.55–58. Orlando, FL: International Institute of Informatics and Systemics.Den Hartog, J. I., de Vink, E. P., & de Bakker, J. W. (2001). Metric Semantics and Full Abstractness for Action Refinement and Probabilistic Choice. Electronic Notes in Theoretical Computer Science, 40, 72-99. doi:10.1016/s1571-0661(05)80038-6Künzi, H.-P. A. (2001). Nonsymmetric Distances and Their Associated Topologies: About the Origins of Basic Ideas in the Area of Asymmetric Topology. History of Topology, 853-968. doi:10.1007/978-94-017-0470-0_3Medina, J., Ojeda-Aciego, M. and Ruiz-Calviño, J. A fixed point theorem for multi-valued functions with an application to multilattice-based logic programming. Applications of Fuzzy Sets Theory: 7th International Workshop on Fuzzy Logic and Applications, WILF 2007, Camogli, Italy, July 7–10, 2007, Proceedings. Edited by: Masulli, F., Mitra, S. and Pasi, G. Vol. 4578, pp.37–44. Berlin: Springer-Verlag. Notes in Artificial IntelligenceO’Keeffe, M., Romaguera, S., & Schellekens, M. (2003). Norm-weightable Riesz Spaces and the Dual Complexity Space. Electronic Notes in Theoretical Computer Science, 74, 105-121. doi:10.1016/s1571-0661(04)80769-2Rodríguez-López, J., Romaguera, S., & Valero, O. (2004). Asymptotic Complexity of Algorithms via the Nonsymmetric Hausdorff Distance. Computing Letters, 2(3), 155-161. doi:10.1163/157404006778330816Rodríguez-López, J., Romaguera, S., & Valero, O. (2008). Denotational semantics for programming languages, balanced quasi-metrics and fixed points. International Journal of Computer Mathematics, 85(3-4), 623-630. doi:10.1080/00207160701210653Romaguera, S., & Schellekens, M. (1999). Quasi-metric properties of complexity spaces. Topology and its Applications, 98(1-3), 311-322. doi:10.1016/s0166-8641(98)00102-3Romaguera, S., & Schellekens, M. (2000). The quasi-metric of complexity convergence. Quaestiones Mathematicae, 23(3), 359-374. doi:10.2989/16073600009485983Romaguera, S., & Schellekens, M. P. (2002). Duality and quasi-normability for complexity spaces. Applied General Topology, 3(1), 91. doi:10.4995/agt.2002.2116Romaguera, S., & Valero, O. (2008). On the structure of the space of complexity partial functions. International Journal of Computer Mathematics, 85(3-4), 631-640. doi:10.1080/00207160701210117Romaguera, S., Sánchez-Pérez, E. A., & Valero, O. (2003). The complexity space of a valued linearly ordered set. Electronic Notes in Theoretical Computer Science, 74, 158-171. doi:10.1016/s1571-0661(04)80772-2Schellekens, M. (1995). The Smyth Completion. Electronic Notes in Theoretical Computer Science, 1, 535-556. doi:10.1016/s1571-0661(04)00029-5Schellekens, M. 1995. “The smyth completion: A common topological foundation for denotational semantics and complexity analysis”. Pittsburgh: Carnegie Mellon University. Ph.D. thesisSeda, A. K., & Hitzler, P. (2008). Generalized Distance Functions in the Theory of Computation. The Computer Journal, 53(4), 443-464. doi:10.1093/comjnl/bxm108Straccia, U., Ojeda-Aciego, M., & Damásio, C. V. (2009). On Fixed-Points of Multivalued Functions on Complete Lattices and Their Application to Generalized Logic Programs. SIAM Journal on Computing, 38(5), 1881-1911. doi:10.1137/070695976Tennent, R. D. (1976). The denotational semantics of programming languages. Communications of the ACM, 19(8), 437-453. doi:10.1145/360303.360308Tix, R., Keimel, K., & Plotkin, G. (2005). RETRACTED: Semantic Domains for Combining Probability and Non-Determinism. Electronic Notes in Theoretical Computer Science, 129, 1-104. doi:10.1016/j.entcs.2004.06.06

Preliminary proceedings of the 2001 ACM SIGPLAN Haskell workshop

This volume contains the preliminary proceedings of the 2001 ACM SIGPLAN Haskell Workshop, which was held on 2nd September 2001 in Firenze, Italy. The final proceedings will published by Elsevier Science as an issue of Electronic Notes in Theoretical Computer Science (Volume 59). The HaskellWorkshop was sponsored by ACM SIGPLAN and formed part of the PLI 2001 colloquium on Principles, Logics, and Implementations of high-level programming languages, which comprised the ICFP/PPDP conferences and associated workshops. Previous Haskell Workshops have been held in La Jolla (1995), Amsterdam (1997), Paris (1999), and Montr´eal (2000). The purpose of the Haskell Workshop was to discuss experience with Haskell, and possible future developments for the language. The scope of the workshop included all aspects of the design, semantics, theory, application, implementation, and teaching of Haskell. Submissions that discussed limitations of Haskell at present and/or proposed new ideas for future versions of Haskell were particularly encouraged. Adopting an idea from ICFP 2000, the workshop also solicited two special classes of submissions, application letters and functional pearls, described below

Logical Specification and Analysis of Fault Tolerant Systems through Partial Model Checking

This paper presents a framework for a logical characterisation of fault tolerance and its formal analysis based on partial model checking techniques. The framework requires a fault tolerant system to be modelled using a formal calculus, here the CCS process algebra. To this aim we propose a uniform modelling scheme in which to specify a formal model of the system, its failing behaviour and possibly its fault-recovering procedures. Once a formal model is provided into our scheme, fault tolerance - with respect to a given property - can be formalized as an equational µ-calculus formula. This formula expresses in a logic formalism, all the fault scenarios satisfying that fault tolerance property. Such a characterisation understands the analysis of fault tolerance as a form of analysis of open systems and thank to partial model checking strategies, it can be made independent on any particular fault assumption. Moreover this logical characterisation makes possible the fault-tolerance verification problem be expressed as a general µ-calculus validation problem, for solving which many theorem proof techniques and tools are available. We present several analysis methods showing the flexibility of our approach