Publications related to On quadratic matrix equations with infinite size coefficients encountered in QBD stochastic processes

On the fast assemblage of finite element matrices with application to nonlinear heat transfer problems

The finite element method is a well-established method for the numerical solution of partial differential equations (PDEs), both linear and nonlinear. However, the repeated re -assemblage of finite element matrices for nonlinear PDEs is frequently pointed ...

ELSEVIER SCIENCE INC2023

Iterative refinement of Schur decompositions

Daniel Kressner, Zvonimir Bujanovic

The Schur decomposition of a square matrix A is an important intermediate step of state-of-the-art numerical algorithms for addressing eigenvalue problems, matrix functions, and matrix equations. This work is concerned with the following task: Compute a (m ...

SPRINGER2022

Positive moments for scattering amplitudes

Riccardo Rattazzi, Francesco Riva, Brando Bellazzini, Marc Riembau Saperas

We find the complete set of conditions satisfied by the forward 2 -> 2 scattering amplitude in unitary and causal theories. These are based on an infinite set of energy dependent quantities (the arcs) which are dispersively expressed as moments of a positi ...

AMER PHYSICAL SOC2021

Compress-and-restart block Krylov subspace methods for Sylvester matrix equations

Daniel Kressner, Stefano Massei, Kathryn Dianne Lund

Block Krylov subspace methods (KSMs) comprise building blocks in many state-of-the-art solvers for large-scale matrix equations as they arise, for example, from the discretization of partial differential equations. While extended and rational block Krylov ...

2020

The time-dependent expected reward and deviation matrix of a finite QBD process

Sophie Myriam Hautphenne

Deriving the time-dependent expected reward function associated with a continuous-time Markov chain involves the computation of its transient deviation matrix. In this paper we focus on the special case of a finite quasi-birth-and-death (QBD) process, moti ...

ELSEVIER SCIENCE INC2019

MATHICSE Technical Report : Low-rank updates and divide-andconquer methods for quadratic matrix equations

Daniel Kressner, Stefano Massei

In this work, we consider two types of large-scale quadratic matrix equations: Continuous-time algebraic Riccati equations, which play a central role in optimal and robust control, and unilateral quadratic matrix equations, which arise from stochastic proc ...

MATHICSE2019

Spectral gaps of frustration-free spin systems with boundary

Marius Christopher Lemm

In quantum many-body systems, the existence of a spectral gap above the ground state has far-reaching consequences. In this paper, we discuss “finite-size” criteria for having a spectral gap in frustration-free spin systems and their applications. We exten ...

2019

Rationally almost periodic sequences, polynomial multiple recurrence and symbolic dynamics

Florian Karl Richter

A set

R\subset \mathbb{N}

is called rational if it is well approximable by finite unions of arithmetic progressions, meaning that for every

\unicode[STIX]{x1D716}>0

there exists a set

B=\bigcup _{i=1}^{r}a_{i}\mathbb{N}+b_{i}

, where $a_{1},\ldots ,a_ ...

2019

Modeling spatially dependent functional data via regression with differential regularization

Fabio Nobile, Eleonora Arnone

We propose a method for modelling spatially dependent functional data, based on regression with differential regularization. The regularizing term enables to include problem-specific information about the spatio-temporal variation of phenomenon under study ...

2019

Low-Rank Updates And A Divide-And-Conquer Method For Linear Matrix Equations

Daniel Kressner, Stefano Massei

Linear matrix equations, such as the Sylvester and Lyapunov equations, play an important role in various applications, including the stability analysis and dimensionality reduction of linear dynamical control systems and the solution of partial differentia ...

SIAM PUBLICATIONS2019

On quadratic matrix equations with infinite size coefficients encountered in QBD stochastic processes

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On the fast assemblage of finite element matrices with application to nonlinear heat transfer problems

Iterative refinement of Schur decompositions

Positive moments for scattering amplitudes

Compress-and-restart block Krylov subspace methods for Sylvester matrix equations

The time-dependent expected reward and deviation matrix of a finite QBD process

MATHICSE Technical Report : Low-rank updates and divide-andconquer methods for quadratic matrix equations

Spectral gaps of frustration-free spin systems with boundary

Rationally almost periodic sequences, polynomial multiple recurrence and symbolic dynamics

Modeling spatially dependent functional data via regression with differential regularization

Low-Rank Updates And A Divide-And-Conquer Method For Linear Matrix Equations

On the fast assemblage of finite element matrices with application to nonlinear heat transfer problems

Spectral gaps of frustration-free spin systems with boundary

Iterative refinement of Schur decompositions

Positive moments for scattering amplitudes

Low-Rank Updates And A Divide-And-Conquer Method For Linear Matrix Equations

The time-dependent expected reward and deviation matrix of a finite QBD process

Compress-and-restart block Krylov subspace methods for Sylvester matrix equations

MATHICSE Technical Report : Low-rank updates and divide-andconquer methods for quadratic matrix equations

Rationally almost periodic sequences, polynomial multiple recurrence and symbolic dynamics

Modeling spatially dependent functional data via regression with differential regularization