In this work we give all the order-two hypergeometric operators D, symmetric with respect to some 2 × 2 irreducible matrix-weight W on (0,1) such that DPn=Pnλn00μn with no repetition among the eigenvalues {λn,μn}n∈N0 , ...

In this paper, we discuss the notion of reducibility of matrix weights and introduce a real vector space CR which encodes all information about the reducibility of W. In particular, a weight W reduces if and only if there ...

In this article we study in detail algebraic properties of the algebra D(W) of differential operators associated to a matrix weight of Gegenbauer type. We prove that two secondorder operators generate the algebra, indeed ...

The practice of spatial econometrics revolves around a weighting matrix, which is often supplied by the user on previous knowledge. This is the so called W issue and, probably, the aprioristic approach is not the best ...

Aluminum matrix composites are currently considered as promising materials for tribological applications in the automotive, aircraft and aerospace industries due to their great advantage of a high strength-to-weight ratio. ...

We establish a necessary and sufficient condition for the existence of the precision matrix estimator obtained by minimizing the negative Gaussian log-likelihood plus a weighted bridge penalty. This condition enables us ...

We introduce matrix-valued weight functions of arbitrary size, which are analogues of the weight function for the Gegenbauer or ultraspherical polynomials for the parameter ν> 0. The LDU-decomposition of the weight is ...