LINEAR ALGEBRA AND ITS APPLICATIONS Special issue on Matrices and Mathematical Biology Call for papers In the last decade the field of mathematical biology has expanded very rapidly. Biological research furnishes both data on and insight into the workings of biological systems. However, qualitative and quantitative modelling and simulation are still far from allowing current knowledge to be organized into a well-understood structure. Further, the diversity present in mathematical biology, coupled with the absence of a single unifying approach, has inspired the formation of entirely new scientific disciplines such as bioinformatics. Theoretical research activity in mathematical biology is naturally of an interdisciplinary character. It involves mathematical and statistical investigations, sometimes in combination with techniques originating from the computational sciences. In many of these approaches, linear algebra is key to solving the mathematical problems which arise. For instance, in some population models, the asymptotic rate of increase of the population turns out to be the spectral radius of a certain matrix associated with the population, while the other eigenvalues also yield information on the evolution of the population's structure. Conversely, problems in mathematical biology can enrich linear algebra. For example, in attempting to measure the influence of a single matrix entry on a simple eigenvalue, linear algebraists frequently employ the derivative of that eigenvalue with respect to the entry. However, some biologists have proposed the use of the elasticity, or a logarithmic derivative, of an eigenvalue with respect to a matrix entry in order to measure the effect on that eigenvalue of perturbing a matrix entry. Thus linear algebraists are challenged to deepen and develop the understanding of the ways in which the effects of changes in the ecological conditions on the populations can be measured through further theoretical investigations. A recent book by Caswell on matrix population models makes extensive use of linear algebraic techniques. Quoting from the introduction to that book: "Matrix population models -- carefully constructed, correctly analyzed, and properly interpreted - provide a theoretical basis for population models... A goal of this book is to raise the bar of what constitutes rigorous analysis in population models.... The work of the population biologist is too important to settle for less." But Caswell's call for careful mathematical construction and analysis applies to areas beyond the subject of population models; clearly a rigorous approach would benefit all areas of interaction between biology and mathematics. The Special Issue of LAA dedicated to Matrices and Mathematical Biology is intended to both foster and accelerate cross fertilization between those working primarily in linear algebra and those working primarily in mathematical biology. The editors hope that such an issue of LAA will be of benefit to both fields. This special issue will be open for all submissions containing new and meaningful results that advance interaction between linear algebra and mathematical biology. The editors welcome submissions in which linear algebraic methods play an important role for novel approaches to problems arising in mathematical biology, or in which investigations in mathematical biology motivate new tools and problems in linear algebra. Survey papers which discuss specific areas involving the interaction between biology and linear algebra, particularly where such interaction has been successful, are also very welcome. Areas and topics of interest for the special issue include, but are not limited to: metabolistic pathways statistical data analysis linear algebra problems in graph partitioning matrix population models model discrimination in biokinetics linear algebra problems in network analysis and synchronization subspace oriented eigenvalue problems aggregation/disaggregation or related techniques hidden Markov models epidemic models modelling phylogenetic trees All papers submitted must meet the publication standards of Linear Algebra and its Applications and will be refereed in the usual way. They should be submitted to one of the special editors of this issue listed below by 30 November 2003. Michael Dellnitz Department of Mathematics and Computer Science University of Paderborn D-33095 Paderborn Germany dellnitz@upb.de Steve Kirkland Department of Mathematics and Statistics University of Regina Regina, Saskatchewan Canada S4S 0A2 kirkland@math.uregina.ca Michael Neumann Department of Mathematics University of Connecticut Storrs, Connecticut O6269-3OO9 USA neumann@math.uconn.edu Christof Schuette Department of Mathematics & Computer Science Numerical Mathematics/Scientific Computing Free University Berlin Arnimallee 2-6 D-14195 Berlin Germany schuette@math.fu-berlin.de