Prepublicacions del Centre de Recerca Matemàtica: Envíos recientes
Mostrando ítems 61-80 de 619
Measurements of Riemannian two-disks and two-spheres
We prove that any Riemannian two-sphere with area at most $ 1$ can be continuously mapped onto a tree in a such a way that the topology of fibers is controlled and their length is less than $ 7.6$ . This result improves ...
Data-driven prediction of thresholded time series of rainfall and SOC models
We study the occurrence of events, subject to threshold, in a representative SOC sandpile model and in high-resolution rainfall data. The predictability in both systems is analyzed by means of a decision variable sensitive ...
Mathematical modelling of phase change with a flowing thin film
This paper concerns the practical applications and modelling of Stefan problems with a flowing thin liquid layer. The modelling will be discussed in the context of two practically important scenarios, Leidenfrost (when a ...
On the scaling behavior of the earthquake inter-time distribution: Influence of large shocks and time scales in the Omori law
We present a study of the earthquake inter-time distribution \linebreak $ D(\Delta t)$ for a California catalog in temporal periods of short duration $ T$ . We compare experimental results with theoretical predictions and ...
On the non-existence of right almost split maps
We show that, over any ring, a module $ C$ is a codomain of a~right almost split map \iff $ C$ is a finitely presented module with local endomorphism ring; thus we give an answer to a 40 years old question by M. Auslander. ...
On the order of the triginometric diameter of the anisotropic Nikol'\''skii--Besov class in the metric of anisotropic Lorentz spaces
In this paper we estimate the order of the triginometric diameters of the anisotropic Nikol'\''skii--Besov classes in the anisotropic Lorentz space.
Geometry of infinitely presented small cancellation groups, Rapid Decay and quasi-homomorphisms
We study the geometry of infinitely presented groups satisfying the small cancelation condition $ C'\''(1/8)$ , and define a standard decomposition (called the \dec decomposition) for the elements of such groups. We use ...
Efficient wavelets-based valuation of synthetic CDO tranches
We present new formulae for the valuation of synthetic collateralized debt obligation (CDO) tranches under the one-factor Gaussian copula model. These formulae are based on the wavelet theory and the method used is called ...
Mather invariants in groups of piecewise-linear homeomorphisms
We describe the relation between two characterizations of conjugacy in groups of piecewise-linear homeomorphisms, discovered by Brin and Squier in \cite{brin2} and Kassabov and Matucci in \cite{kama}. Thanks to the interplay ...
MULTIGRID PRECONDITIONER FOR NONCONFORMING DISCRETIZATION OF ELLIPTIC PROBLEMS WITH JUMP COEFFICIENTS
linear system arising from the piecewise linear nonconforming Crouzeix-Raviart discretization of second order elliptic problems with jump coefficients. The preconditioner uses the standard conforming subspaces as coarse ...
Modelling the solidification of a power-law fluid flowing through a narrow pipe
We develop a mathematical model to simulate the solidification process of a non-Newtonian power-law fluid flowing through a circular cross-section microchannel. The initial system consists of three partial differential ...
Order reduction for a model of marine bacteriophage evolution
A typical mechanistic model of viral evolution necessary includes several time scales which can differ by orders of magnitude. Such a diversity of time scales makes analysis of these models difficult. Reducing the order ...
Cartesian modules over representations of small categories
We introduce the new concept of cartesian module over a pseudofunctor $ R$ from a small category to the category of small preadditive categories. Already the case when $ R$ is a (strict) functor taking values in the ...
Deviation from power law of the global seismic moment distribution
The distribution of seismic moment is of capital interest to evaluate earthquake hazard, in particular regarding the most extreme events. We make use of likelihood-ratio tests to compare the simple Gutenberg-Richter power-law ...
Finite-size scaling of survival probability in branching processes
Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We reveal the finite-size scaling law of ...
Just-infinite $ C^*$ -algebras and their invariants
Just-infinite C* s, i.e., infinite dimensional C* s, whose proper quotients are finite dimensional, were investigated in \cite{GMR:JI}. One particular example of a just-infinite residually finite dimensional AF-algebras ...
Order reduction for an RNA virus evolution model
A mathematical or computational model in evolutionary biology should necessary combine several comparatively fast processes, which actually drive natural selection and evolution, with a very slow process of evolution. As ...
Explicit focal basis for some planar rigid polynomial differential systems
In general the center--focus problem cannot be solved, but in the case that the singularity has purely imaginary eigenvalues there are algorithms to solving it. The present paper implements one of these algorithms for the ...
Global properties for SIR and SEIR age-structured models
We consider global asymptotic properties for the \emph{SIR} and \emph{SEIR} age structured models for infectious diseases where the susceptibility depends on the age. Using the direct Lyapunov method with Volterra type ...
