Among methods to analyze high-dimensional data, the sliced inverse regression (SIR) is of particular interest for non-linear relations between the dependent variable and some indices of the covariate. When the dimension of the covariate is greater than the number of observations, classical versions of SIR cannot be applied. Various upgrades were then proposed to tackle this issue such as RSIR a...

Let f be a function transcendental and meromorphic in the plane with lim inf r→∞ T (r, f) (log r)2 = 0. Let q ∈ C with |q| > 1. It is shown that at least one of the functions F (z) = f(qz)− f(z), G(z) = F (z) f(z) has infinitely many zeros. This result is sharp. MSC 2000: 30D35.

A unified deflating subspace approach is presented for the solution of a large class of matrix equations, including Lyapunov, Sylvester, Riccati and also some higher order polynomial matrix equations including matrix m-th roots and matrix sector functions. A numerical method for the computation of the desired deflating subspace is presented that is based on adapted versions of the periodic QZ a...

Classes of‎ ‎Abaffy-Broyden-Spedicato (ABS) methods have been introduced for‎ ‎solving linear systems of equations‎. ‎The algorithms are powerful methods for developing matrix‎ ‎factorizations and many fundamental numerical linear algebra processes‎. ‎Here‎, ‎we show how to apply the ABS algorithms to devise algorithms to compute the WZ and ZW‎ ‎factorizations of a nonsingular matrix as well as...

Structure-preserving numerical techniques for computation of eigenvalues and stable deflating subspaces of complex skew-Hamiltonian/Hamiltonian matrix pencils, with applications in control systems analysis and design, are presented. The techniques use specialized algorithms to exploit the structure of such matrix pencils: the skew-Hamiltonian/Hamiltonian Schur form decomposition and the periodi...

It is well-known that Euclid’s argument can be adapted to prove the infinitude of primes of the form 4k − 1. We describe a simple proof that the sum of the reciprocals of all such primes diverges. More generally, if q is a positive integer, and H is a proper subgroup of the units group (Z/qZ)×, we show that ∑ p prime p mod q 6∈H 1 p =∞.

Computing roots of a monic polynomial may be done by computing the eigenvalues of the corresponding companion matrix using for instance the well-known QR-algorithm. We know this algorithm to be backward stable since it computes exact eigenvalues of a slightly modified matrix. But it may yield very poor backward errors in the coefficients of the polynomial. In this paper we investigate what can ...

In this paper, we will describe the mathematical foundation of topological Landau–Ginzburg (LG) models coupled to gravity at genus 0 in terms of primitive forms. In particular, we can give a natural explanation for the large phase space. We also discuss the mirror symmetry for Calabi–Yau manifolds and CP1 in our context. We see that the mirror partner of CP1 is the theory of primitive form asso...

In this paper we present a method for using rational expectations in a stochastic linear-quadratic optimization framework in which the unknown parameters are updated through a learning scheme. We use the QZ decomposition as suggested by Sims (1996) to solve the rational expectations part of the model. The parameter updating is done with the Kalman filter and the optimal control is calculated us...