共查询到20条相似文献,搜索用时 15 毫秒
1.
Ozhan Genc 《Journal of Pure and Applied Algebra》2018,222(1):213-240
In this paper, we consider the existence problem of rank one and two stable Ulrich bundles on imprimitive Fano 3-folds obtained by blowing-up one of , Q (smooth quadric in ), (smooth cubic in ) or (complete intersection of two quadrics in ) along a smooth irreducible curve. We prove that the only class which admits Ulrich line bundles is the one obtained by blowing up a genus 3, degree 6 curve in . Also, we prove that there exist stable rank two Ulrich bundles with on a generic member of this deformation class. 相似文献
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Manuel D. de la Iglesia Pablo Román 《Stochastic Processes and their Applications》2018,128(10):3300-3326
The aim of this paper is to study some continuous-time bivariate Markov processes arising from group representation theory. The first component (level) can be either discrete (quasi-birth-and-death processes) or continuous (switching diffusion processes), while the second component (phase) will always be discrete and finite. The infinitesimal operators of these processes will be now matrix-valued (either a block tridiagonal matrix or a matrix-valued second-order differential operator). The matrix-valued spherical functions associated to the compact symmetric pair will be eigenfunctions of these infinitesimal operators, so we can perform spectral analysis and study directly some probabilistic aspects of these processes. Among the models we study there will be rational extensions of the one-server queue and Wright–Fisher models involving only mutation effects. 相似文献
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A second order asymptotic expansion in the local limit theorem for a simple branching random walk in
Zhi-Qiang Gao 《Stochastic Processes and their Applications》2018,128(12):4000-4017
Consider a branching random walk, where the underlying branching mechanism is governed by a Galton–Watson process and the migration of particles by a simple random walk in . Denote by the number of particles of generation located at site . We give the second order asymptotic expansion for . The higher order expansion can be derived by using our method here. As a by-product, we give the second order expansion for a simple random walk on , which is used in the proof of the main theorem and is of independent interest. 相似文献
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Simone Franchini 《Stochastic Processes and their Applications》2017,127(10):3372-3411
We consider a generalized two-color Polya urn (black and white balls) first introduced by Hill et al. (1980), where the urn composition evolves as follows: let , and denote by the fraction of black balls after step , then at step a black ball is added with probability and a white ball is added with probability . Originally introduced to mimic attachment under imperfect information, this model has found applications in many fields, ranging from Market Share modeling to polymer physics and biology.In this work we discuss large deviations for a wide class of continuous urn functions . In particular, we prove that this process satisfies a Sample-Path Large Deviations principle, also providing a variational representation for the rate function. Then, we derive a variational representation for the limit where is the number of black balls at time , and use it to give some insight on the shape of . Under suitable assumptions on we are able to identify the optimal trajectory. We also find a non-linear Cauchy problem for the Cumulant Generating Function and provide an explicit analysis for some selected examples. In particular we discuss the linear case, which embeds the Bagchi–Pal Model [6], giving the exact implicit expression for in terms of the Cumulant Generating Function. 相似文献
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Jérémie Unterberger 《Stochastic Processes and their Applications》2018,128(12):4104-4153
We study in this article the hydrodynamic limit in themacroscopic regime of the coupled system of stochastic differential equations,
(0.1)
with , sometimes called generalized Dyson’s Brownian motion, describing the dissipative dynamics of a log-gas of equal charges with equilibrium measure corresponding to a -ensemble, with sufficiently regular convex potential . The limit is known to satisfy a mean-field Mc-Kean–Vlasov equation. We prove that, for suitable initial conditions, fluctuations around the limit are Gaussian and satisfy an explicit PDE.The proof is very much indebted to the harmonic potential case treated in Israelsson (2001). Our key argument consists in showing that the time-evolution generator may be written in the form of a transport operator on the upper half-plane, plus a bounded non-local operator interpreted in terms of a signed jump process. 相似文献
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In this work, we prove the existence of convex solutions to the following k-Hessian equation in the neighborhood of a point , where , is nonnegative near , and . 相似文献
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For Komatu–Loewner equation on a standard slit domain, we randomize the Jordan arc in a manner similar to that of Schramm (2000) to find the SDEs satisfied by the induced motion on and the slit motion . The diffusion coefficient and drift coefficient of such SDEs are homogeneous functions.Next with solutions of such SDEs, we study the corresponding stochastic Komatu–Loewner evolution, denoted as . We introduce a function measuring the discrepancy of a standard slit domain from relative to BMD. We show that enjoys a locality property. 相似文献
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Umut Çetin 《Stochastic Processes and their Applications》2018,128(10):3439-3465
Let be a regular one-dimensional transient diffusion and be its local time at . The stochastic differential equation (SDE) whose solution corresponds to the process conditioned on for a given is constructed and a new path decomposition result for transient diffusions is given. In the course of the construction Bessel-type motions as well as their SDE representations are studied. Moreover, the Engelbert–Schmidt theory for the weak solutions of one dimensional SDEs is extended to the case when the initial condition is an entrance boundary for the diffusion. This extension was necessary for the construction of the Bessel-type motion which played an essential part in the SDE representation of conditioned on . 相似文献
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This paper considers the martingale problem for a class of weakly coupled Lévy type operators. It is shown that under some mild conditions, the martingale problem is well-posed and uniquely determines a strong Markov process . The process , called a regime-switching jump diffusion with Lévy type jumps, is further shown to possess Feller and strong Feller properties under non-Lipschitz conditions via the coupling method. 相似文献
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Paolo Albano Piermarco Cannarsa Teresa Scarinci 《Journal of Differential Equations》2018,264(5):3312-3335
In a bounded domain of with boundary given by a smooth -dimensional manifold, we consider the homogeneous Dirichlet problem for the eikonal equation associated with a family of smooth vector fields subject to Hörmander's bracket generating condition. We investigate the regularity of the viscosity solution T of such problem. Due to the presence of characteristic boundary points, singular trajectories may occur. First, we characterize these trajectories as the closed set of all points at which the solution loses point-wise Lipschitz continuity. Then, we prove that the local Lipschitz continuity of T, the local semiconcavity of T, and the absence of singular trajectories are equivalent properties. Finally, we show that the last condition is satisfied whenever the characteristic set of is a symplectic manifold. We apply our results to several examples. 相似文献
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Gianfranco Casnati Daniele Faenzi Francesco Malaspina 《Journal of Pure and Applied Algebra》2018,222(3):585-609
In the present paper we completely classify locally free sheaves of rank 2 with vanishing intermediate cohomology modules on the image of the Segre embedding and its general hyperplane sections.Such a classification extends similar already known results regarding del Pezzo varieties with Picard numbers 1 and 3 and dimension at least 3. 相似文献
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Let be a purely discontinuous additive functional of a subordinate Brownian motion . We give a sufficient condition on the non-negative function that guarantees that finiteness of implies finiteness of its expectation. This result is then applied to study the relative entropy of and the probability measure induced by a purely discontinuous Girsanov transform of the process . We prove these results under the weak global scaling condition on the Laplace exponent of the underlying subordinator. 相似文献
14.
Zhuo Min Lim 《Journal of Differential Equations》2018,264(4):2553-2597
We consider the initial-value problem for the Chern–Simons–Schrödinger system, which is a gauge-covariant Schrödinger system in with a long-range electromagnetic field. We show that, in the Coulomb gauge, it is locally well-posed in for , and the solution map satisfies a local-in-time weak Lipschitz bound. By energy conservation, we also obtain a global regularity result. The key is to retain the non-perturbative part of the derivative nonlinearity in the principal operator, and exploit the dispersive properties of the resulting paradifferential-type principal operator using adapted and spaces. 相似文献
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Christophe Cuny Jérôme Dedecker Florence Merlevède 《Stochastic Processes and their Applications》2018,128(4):1347-1385
The famous results of Komlós, Major and Tusnády (see Komlós et al., 1976 [15] and Major, 1976 [17]) state that it is possible to approximate almost surely the partial sums of size of i.i.d. centered random variables in () by a Wiener process with an error term of order . Very recently, Berkes et al. (2014) extended this famous result to partial sums associated with functions of an i.i.d. sequence, provided a condition on a functional dependence measure in is satisfied. In this paper, we adapt the method of Berkes, Liu and Wu to partial sums of functions of random iterates. Taking advantage of the Markovian setting, we shall give new dependent conditions, expressed in terms of a natural coupling (in or in ), under which the strong approximation result holds with rate . As we shall see our conditions are well adapted to a large variety of models, including left random walks on , contracting iterated random functions, autoregressive Lipschitz processes, and some ergodic Markov chains. We also provide some examples showing that our -coupling condition is in some sense optimal. 相似文献
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We consider a -dimensional random field that solves a system of elliptic stochastic equations on a bounded domain , with additive white noise and spatial dimension . Properties of and its probability law are proved. For Gaussian solutions, using results from Dalang and Sanz-Solé (2009), we establish upper and lower bounds on hitting probabilities in terms of the Hausdorff measure and Bessel–Riesz capacity, respectively. This relies on precise estimates of the canonical distance of the process or, equivalently, on estimates of increments of the Green function of the Laplace equation. 相似文献
18.
Huyuan Chen Patricio Felmer Jianfu Yang 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2018,35(3):729-750
In this paper, we study the elliptic problem with Dirac mass
(1)
where , , , is the Dirac mass at the origin and the potential V is locally Lipchitz continuous in , with non-empty support and satisfying with , and . We obtain two positive solutions of (1) with additional conditions for parameters on , p and k. The first solution is a minimal positive solution and the second solution is constructed via Mountain Pass Theorem. 相似文献
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