Centre de Recerca Matemàtica: Enviaments recents
Ara mostrant els elements 281-300 de 1369
Existence of at most two limit cycles for some non-autonomous differential equations
It is know that the non-autonomous differential equations dx/dt = a(t)+b(t)|x|, where a(t) and b(t) are 1-periodic maps of class C1, have no upper bound for their number of limit cycles (isolated solutions satisfying x(0) ...
Contact structures with singularities: From local to global
In this article we introduce and analyze in detail singular contact structures, with an emphasis on bm-contact structures, which are tangent to a given smooth hypersurface Z and satisfy certain transversality conditions. ...
Designing Weights for Quartet-Based Methods When Data are Heterogeneous Across Lineages
Homogeneity across lineages is a general assumption in phylogenetics according to which nucleotide substitution rates are common to all lineages. Many phylogenetic methods relax this hypothesis but keep a simple enough ...
Constructions of b-semitoric systems
In this article, we introduce b-semitoric systems as a generalization of semitoric systems, specifically tailored for b-symplectic manifolds. The objective of this article is to furnish a collection of examples and investigate ...
Asymptotic Self-Similar Blow-Up Profile for Three-Dimensional Axisymmetric Euler Equations Using Neural Networks
Whether there exist finite-time blow-up solutions for the 2D Boussinesq and the 3D Euler equations are of fundamental importance to the field of fluid mechanics. We develop a new numerical framework, employing physics-informed ...
Cyclicity Near Infinity in Piecewise Linear Vector Fields Having a Nonregular Switching Line
In this paper we recover the best lower bound for the number of limit cycles in the planar piecewise linear class when one vector field is defined in the first quadrant and a second one in the others. In this class and ...
Breakdown of homoclinic orbits to L3 in the RPC3BP (II). An asymptotic formula
The Restricted 3-Body Problem models the motion of a body of negligible mass under the gravitational influence of two massive bodies called the primaries. If one assumes that the primaries perform circular motions and that ...
Random Cubic Planar Maps
We analyse uniform random cubic rooted planar maps and obtain limiting distributions for several parameters of interest. From the enumerative point of view, we present a unified approach for the enumeration of several ...
Well-posedness of heat and wave equations generated by Rubin’s q-difference operator in Sobolev spaces
In this paper, we investigate difference-differential operators of parabolic and hyperbolic types. Namely, we consider non-homogenous heat and wave equations for Rubin’s difference operator. Well-posedness results are ...
Dimension of representation and character varieties for two-and three-orbifolds
We consider varieties of representations and characters of 2 and 3 dimensional orbifolds in semisimple Lie groups, and we focus on computing their dimension. For hyperbolic 3 orbifolds, we consider the component of the ...
A METHOD TO COARSE-GRAIN MULTIAGENT STOCHASTIC SYSTEMS WITH REGIONS OF MULTISTABILITY
Hybrid multiscale modeling has emerged as a useful framework for modeling complex biological phenomena. However, when accounting for stochasticity in the internal dynamics of agents, these models frequently become ...
A practical guide for studying human behavior in the lab
In the last few decades, the field of neuroscience has witnessed major technological advances that have allowed researchers to measure and control neural activity with great detail. Yet, behavioral experiments in humans ...
THE EMBEDDING PROBLEM FOR MARKOV MATRICES
Characterizing whether a Markov process of discrete random variables has a homogeneous continuous-time realization is a hard problem. In practice, this problem reduces to deciding when a given Markov matrix can be written ...
ON INVARIANT RANK TWO VECTOR BUNDLES ON P2
In this paper we characterize the rank two vector bundles on P2 which are invariant under the actions of the parabolic subgroups Gp := Stabp(PGL(3)) fixing a point in the projective plane, GL := StabL(PGL(3)) fixing a line, ...
Logan's problem for Jacobi transforms
We consider direct and inverse Jacobi transforms with measures [equaction presented] respectively. We solve the following generalized Logan problem: to find inf Λ ((−1) m−1 f ) , m ∈ N, where Λ (f ) = sup {λ > 0: f (λ) ...
Semiclassical theory predicts stochastic ghosts scaling
Slowing down occurs in dynamical systems close to bifurcations or phase transitions. The time length (τ) of ghost transients close to a saddle-node bifurcation in deterministic systems follows {equation presented} being ...
Invariant manifolds near L1 and L2 in the quasi-bicircular problem
The quasi-bicircular problem (QBCP) is a periodic time-dependent perturbation of the Earth–Moon restricted three-body problem (RTBP) that accounts for the effect of the Sun. It is based on using a periodic solution of the ...
Largest component of subcritical random graphs with given degree sequence
We study the size of the largest component of two models of random graphs with prescribed degree sequence, the configuration model (CM) and the uniform model (UM), in the (barely) subcritical regime. For the CM, we give ...
L2 -Boundedness of Gradients of Single Layer Potentials for Elliptic Operators with Coefficients of Dini Mean Oscillation-Type
We consider a uniformly elliptic operator LA in divergence form associated with an (n+ 1) × (n+ 1) -matrix A with real, merely bounded, and possibly non-symmetric coefficients. If [Equation not available: see fulltext.]then, ...
Sparse Grid Approximation in Weighted Wiener Spaces
We study approximation properties of multivariate periodic functions from weighted Wiener spaces by sparse grid methods constructed with the help of quasi-interpolation operators. The class of such operators includes ...
