Prepublicacions del Centre de Recerca Matemàtica: Recent submissions
Now showing items 41-60 of 619
Pointwise Estimates for $ 3$ -monotone Approximation
We prove that for a $ 3$ -monotone function $ F\in C[-1,1]$ , one can achieve the pointwise estimates \[ |F(x)-\Psi(x)|\le c\omega_3(F,\rho_n(x)), \quad x\in[-1,1], \] where $ \rho_n(x):=\frac1{n^2}+\frac{\sqrt{1-x^2}}n$ ...
Parabolic equations in time dependent domains
We show existence and uniqueness results for nonlinear parabolic equations in noncylindrical domains with possible jumps in the time variable.
On orders of approximation of the generalized Nikol'\''skii--Besov class in Lorentz spaces
This paper considers the Lorentz space with mixed norm of periodic functions of many variables and of the generalized Nikol'\''skii--Besov classes. Estimates for the order of approximation of the generalized Nikol'\''skii--Besov ...
Pitt'\''s and Boas'\'' inequalities for Fourier and Hankel transforms
We prove Pitt and Boas'\'' type inequalities for products of radial functions and spherical harmonics in $ \R^n$ . In the process, we obtain upper and lower estimates of the operator norm of the Hankel transform with power ...
Peaks and Jumps Reconstruction with B-Splines Scaling Functions
We consider a methodology based in B-splines scaling functions to numerically invert Fourier or Laplace transforms. The methodology is particularly well suited when the original function or its derivatives present peaks ...
Description of interpolation spaces for the pair of local Morrey-type spaces and their generalizations
We consider the real interpolation method and prove that for general local Morrey-type spaces, in the case when they have the same integrability parameter, the interpolation spaces are again general local Morrey-type spaces ...
Gorenstein homological algebra and universal coefficient theorems
We study criteria for a ring -- or more generally, for a small category -- to be Gorenstein and for a module over it to be of finite projective dimension. The goal is to unify the universal coefficient theorems found in ...
On an extension of the notion of Reedy category
We extend the classical notion of a Reedy category so as to allow non-trivial automorphisms. Our extension includes many important examples occuring in topology such as Segal'\''s category $ \Gamma$ , or the total category ...
Hamiltonian stability in some open surfaces with simple singularities
We complement to some open surfaces with singularities the basic characterization theorem obtained by Jarque--Nitecki [Ergod. Th. \& Dynam Sys. \textbf{20} (2000) 775--799] for Hamiltonian flows in the Euclidean plane which ...
HIGH ORDER AND ENERGY PRESERVING DISCONTINUOUS GALERKIN METHODS FOR THE VLASOV-POISSON SYSTEM
We present a computational study for a family of discontinuous Galerkin methods for the one dimensional Vlasov-Poisson system, recently introduced in \cite{acs0}. We introduce a slight modification of the methods to allow ...
Highest weight categories and recollements
We provide several equivalent descriptions of a highest weight category using recollements of abelian categories. The settings for this are abelian length categories and $ k$ -linear exact categories, where $ k$ denotes ...
Mathematical modelling of heat exchange in flash tank heat exchanger cascades
Flash tank evaporation combined with a condensing heat exchanger can be used when heat exchange is required between two streams, where at least one of these streams is difficult to handle (tends severely to scale, foul, ...
Hopf bifurcation at infinity and dissipative vector fields of the plane
We describe some families of differentiable vector fields with the Hopf bifurcation at infinity, without assuming the continuous differentiability. These vector fields have isolated singular points on the plane, and the ...
On the limit cycles of a class of Kukles type differential systems
We study the limit cycles of two families of differential systems in the plane. These systems are obtained by polynomial perturbations with arbitrary degree on the second component of the standard linear center. In this ...
Conjugacy in Houghton'\''s Groups
Let $ n\in \N$ . Houghton'\''s group $ H_n$ is the group of permutations of $ \{1,\dots, n\}\times \N$ , that eventually act as a translation in each copy of $ \N$ . We prove the solvability of the conjugacy problem and ...
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 ...
Models order reduction and equivalence: Paradox of enrichment is a 3-dim bacteriophages dynamics model as case study
The paradox of enrichment in a three-dimensional model for bacteriophage dynamics with a free infection stage of the phage and bilinear incident rate is considered. An application of the technique of singular perturbation ...
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 ...
Efficient VaR and Expected Shortfall computations for non-linear portfolios within the delta-gamma approach
We present four numerical methods to compute the Value-at-Risk and Expected Shortfall risk measure values of portfolios with financial options. The numerical methods are based on either wavelets or Fourier cosine approximations ...
