Search results for "Theoretical Computer Science"
showing 10 items of 1151 documents
AC is Equivalent to the Coherence Principle. Corrigendum to my Paper "Induction Principles for Sets"
2009
Theorem 3.7 of [1] is corrected. Two coherence principles and the ultrafilter property for partial functions contained in a relation are formulated. The equivalence of the coherent principles with AC and the equivalence of the ultrafilter property with BPI is shown.
Randomized heuristics for the Capacitated Clustering Problem
2017
In this paper, we investigate the adaptation of the Greedy Randomized Adaptive Search Procedure (GRASP) and Iterated Greedy methodologies to the Capacitated Clustering Problem (CCP). In particular, we focus on the effect of the balance between randomization and greediness on the performance of these multi-start heuristic search methods when solving this NP-hard problem. The former is a memory-less approach that constructs independent solutions, while the latter is a memory-based method that constructs linked solutions, obtained by partially rebuilding previous ones. Both are based on the combination of greediness and randomization in the constructive process, and coupled with a subsequent l…
BMaD – A Boolean Matrix Decomposition Framework
2014
Boolean matrix decomposition is a method to obtain a compressed representation of a matrix with Boolean entries. We present a modular framework that unifies several Boolean matrix decomposition algorithms, and provide methods to evaluate their performance. The main advantages of the framework are its modular approach and hence the flexible combination of the steps of a Boolean matrix decomposition and the capability of handling missing values. The framework is licensed under the GPLv3 and can be downloaded freely at http://projects.informatik.uni-mainz.de/bmad.
Two-variable logics with counting and semantic constraints
2018
In this article we discuss fragments and extensions of two-variable logics motivated by practical applications. We outline the decidability frontier, describing some of the techniques developed for deciding satisfiability and finite satisfiability, as well as characterizing their complexity.
How to control stock markets
1994
This paper provides a different approach to the analysis of imperfect stock markets. The model we are concerned with is described by the interaction of three institutional classes of agents (the specialist trader, the professional trader and the non-professional trader), sharing different information. The dynamical discrete-time system obtained can be changed into a second-order linear difference equation forced by the fundamental value of the specialist trader. Using typical tools of control theory, we study the behaviour of the professional trader’s fundamental value influenced by the specialist’s one. © 1994 Taylor & Francis Group, LLC.
Formal Analysis and Model Checking of a Group Authentication Protocol by Scyther
2016
Scyther [1] is designed to check the security and vulnerabilities of security protocols. In this paper, we use Scyther to analyze two discrete logarithm problem (DLP) based group authentication protocols proposed in [2]. These two protocols are claimed to satisfy several security requirements, but only part of them have been checked because of the properties and limitations of Scyther. Some positive results have been gained and show that the protocols provide mutual authentication and implicit key authentication and are secure against impersonation attack. An important innovation in this paper is that we have extended the expressing ability of Scyther by giving some reasonable assumption du…
A Detailed Account of The Inconsistent Labelling Problem of Stutter-Preserving Partial-Order Reduction
2021
One of the most popular state-space reduction techniques for model checking is partial-order reduction (POR). Of the many different POR implementations, stubborn sets are a very versatile variant and have thus seen many different applications over the past 32 years. One of the early stubborn sets works shows how the basic conditions for reduction can be augmented to preserve stutter-trace equivalence, making stubborn sets suitable for model checking of linear-time properties. In this paper, we identify a flaw in the reasoning and show with a counter-example that stutter-trace equivalence is not necessarily preserved. We propose a stronger reduction condition and provide extensive new correc…
Verification of Well-Formed Communicating Recursive State Machines
2008
AbstractIn this paper we introduce a new (non-Turing equivalent) formal model of recursive concurrent programs called well-formed communicating recursive state machines (CRSM). CRSM extend recursive state machines (RSM) by allowing a restricted form of concurrency: a state of a module can be refined into a finite collection of modules (working in parallel) in a potentially recursive manner. Communication is only possible between the activations of modules invoked on the same fork. We study the model-checking problem of CRSM with respect to specifications expressed in a temporal logic that extends CaRet with a parallel operator (ConCaRet). We propose a decision algorithm that runs in time ex…
Implementing an ATL model checker tool using relational algebra concepts
2014
Alternating-Time Temporal Logic (ATL) is a branching-time temporal logic that naturally describes computations of open systems. An open system interacts with its environment and its behavior depends on the state of the system as well as the behavior of the environment. ATL model-checking is a well-established technique for verifying that a formal model representing such a system satisfies a given property. In this paper we describe a new interactive model checker environment based on algebraic approach. Our tool is implemented in client-server paradigm. The client part allows an interactive construction of ATL models represented by concurrent game structures as directed multi-graphs. The se…
Minimal Büchi Automata for Certain Classes of LTL Formulas
2009
In this paper we calculate the minimal number of states of Buchi automata which encode some classes of linear temporal logic (LTL) formulas that are frequently used in model checking. Our results may be used for verification of the quality of algorithms which automatically translate LTL formulas into Buchi automata and for improving the quality and speed of such translators. In the last section of this paper we compare our lower-bound estimations to Buchi automata generated by two currently used translators: LTL2BA and SPOT.