Research Articles (Mathematical Sciences)
Recent Submissions

On the validity of evolutionary models with sitespecific parameters
(PLoS, 20140410)Evolutionary models that make use of sitespecific parameters have recently been criticized on the grounds that parameter estimates obtained under such models can be unreliable and lack theoretical guarantees of convergence. ...

Spatial assortment of mixed propagules explains the acceleration of range expansion
(Public Library of Science, 201408)Abstract Range expansion of spreading organisms has been found to follow three types: (i) linear expansion with a constant rate of spread; (ii) biphase expansion with a faster linear expansion following a slower linear ...

Model checking rational agents
(IEEE  Institute of Electrical and Electronics Engineers, 200410)Agentoriented programming techniques seem appropriate for developing systems that operate in complex, dynamic, and unpredictable environments. We aim to address this requirement by developing modelchecking techniques for ...

Propertybased slicing for agent verification
(Oxford University Press (OUP), 200912)Programming languages designed specifically for multiagent systems represent a new programming paradigm that has gained popularity over recent years, with some multiagent programming languages being used in increasingly ...

A survey of new trends in symbolic execution for software testing and analysis
(Springer Verlag, 200910)Symbolic execution is a wellknown program analysis technique which represents program inputs with symbolic values instead of concrete, initialized, data and executes the program by manipulating program expressions involving ...

Left ventricular segmentation from MRI datasets with edge modelling conditional random fields
(BioMed Central, 201307)Background: This paper considers automatic segmentation of the left cardiac ventricle in short axis magnetic resonance images. Various aspects, such as the presence of papillary muscles near the endocardium border, makes ...

NonNegative Matrix Factorization for Learning AlignmentSpecific Models of Protein Evolution
(PLOS, 20111222)Models of protein evolution currently come in two flavors: generalist and specialist. Generalist models (e.g. PAM, JTT, WAG) adopt a onesizefitsall approach, where a single model is estimated from a number of different ...

Codon test : modeling amino acid substitution preferences in coding sequences
(PLOS Computational Biology, 201008)Codon models of evolution have facilitated the interpretation of selective forces operating on genomes. These models, however, assume a single rate of nonsynonymous substitution irrespective of the nature of amino acids ...

Modeling HIV1 drug resistance as episodic directional selection
(PLOS Computational Biology, 201105)The evolution of substitutions conferring drug resistance to HIV1 is both episodic, occurring when patients are on antiretroviral therapy, and strongly directional, with sitespecific resistant residues increasing in ...

Correcting the bias of empirical frequency parameter estimators in codon models
(Public Library of Science  PLOS, 201007)Markov models of codon substitution are powerful inferential tools for studying biological processes such as natural selection and preferences in amino acid substitution. The equilibrium character distributions of these ...

The geometry of unitary 2representations of finite groups and their 2characters
(Springer Link, 201102)Motivated by topological quantum field theory, we investigate the geometric aspects of unitary 2representations of finite groups on 2Hilbert spaces, and their 2characters. We show how the basic ideas of geometric ...

Francis Guthrie : a colourful life
(Springer, 201209)In 1852, in London, Francis Guthrie posed the question of colouring a map with four colours only, the question that eventually became known as the Four Colour Problem. The problem is famous, but what else do we know of ...

Realization of abstract convex geometries by point configurations
(Elsevier, 201001)The EdelmanJamison problem is to characterize those abstract convex geometries that are representable by a set of points in the plane. We show that some natural modification of the EdelmanJamison problem is equivalent ...

The asymptotic number of binary codes and binary matroids
(Society for Industrial and Applied Mathematics (SIAM), 200608)The asymptotic number of nonequivalent binary ncodes is determined. This is also the asymptotic number of nonisomorphic binary matroids on n elements.

Die SuidAfrikaanse uitgebreide maritieme gebied : ’n alternatiewe metode vir die bepaling van die voet van die kontinentale helling
(AOSIS OpenJournal, 2006)Kuslande het ’n eenmalige geleentheid om by die Verenigde Nasies (VN) aansoek te doen om ’n uitgebreide maritieme gebied, indien hul wetenskaplik kan toon dat die voet van die kontinentale helling (VKH) buite hul soewereine ...

Decomposing the hypercube Qn into n isomorphic edgedisjoint trees
(Elsevier, 201202)The problem of finding edgedisjoint trees in a hypercube arises for example in the context of parallel computing [3]. Independently of applications it is of high aesthetic appeal. The hypercube of dimension n, denoted ...

Computing various types of lattices freely generated by posets
(Edizioni CERFIM Centro di Ricerche in Fisica e MatematicaResearch Center for Mathematics and Physics  Locarno  Switzerland, 2000)see item for abstract

Special subvarieties of Drinfeld modular varieties
(Walter de Gruyter, 201011)We explore an analogue of the Andr´eOort conjecture for subvarieties of Drinfeld modular varieties. The conjecture states that a subvariety X of a Drinfeld modular variety contains a Zariskidense set of complex ...

Partitioning the hypercube Qn into n isomorphic edgedisjoint trees
(TU Graz University of Technology, 2011)ENGLISH ABSTRACT: The problem of finding edgedisjoint trees in a hypercube e.g. arises in the context of parallel computing. Independent of applications it is of high aesthetic appeal.

Computing the output distribution of a stack filter from the DNF of its positive Boolean function
(Cornell University Library, 2010)ENGLISH ABSTRACT: The majority of nonlinear filters used in practise are stack filters. An algorithm is presented which calculates the output distribution of an arbitrary stack filter S from the disjunctive normal form ...

Calculating the output distribution of stack filters that are erosiondilation cascades, in particular LULUfilters
(Cornell University Library, 2011)ENGLISH ABSTRACT: Two procedures to compute the output distribution 0S of certain stack filters S (so called erosiondilation cascades) are given. One rests on the disjunctive normal form of S and also yields the rank ...

Compactly generating all satisfying truth assignments of a horn formula
(Delft University in cooperation with IOS Press, 201201)ENGLISH ABSTRACT: While it was known that all models of a Horn formula can be generated in outputpolynomial time, here we present an explicit algorithm as opposed to the rather vague oraclescheme suggested in the proof ...