activity
20132026
collaborators

6 papers

math.FA2026

Hyperpositive functions, sector bounded functions and a trace formula

Daniel Alpay, Izchak Lewkowicz

We study an indexed family of functions closely related to functions ana- lytic and with a real positive part in the right open half plane (the so-called positive functions) and to…

math.CV2026

Quantitatively hyper-positive real rational functions IV: The canonical case

Daniel Alpay, Izchak Lewkowicz

In the linear time-invariant framework, passive systems are modeled by positive real functions. Dissipative systems can be modeled by the subset of quantita- tively Hyper-positive…

math.OC2026

Quantitatively hyper-positive real rational functions III

Daniel Alpay, Izchak Lewkowicz

Hyper-Positive Real, matrix-valued, rational functions are associated with absolute stability (the Lurie problem). Here, quantitative subsets of Hyper-positive functions, related t…

math.AP2026

Hardy decomposition of first order Lipschitz functions by Lamé-Navier solutions

Daniel Alfonso Santiesteban, Ricardo Abreu Blaya, Daniel Alpay

The Clifford algebra language allows us to rewrite the Lamé-Navier system in terms of the Euclidean Dirac operator. In this paper, the main question we shall be concerned with is w…

math.AP2025

Jump problem for generalized Lamé-Navier systems in

Daniel Alfonso Santiesteban, Ricardo Abreu Blaya, Daniel Alpay

This paper is devoted to study a fundamental system of equations in Linear Elasticity Theory: the famous Lamé-Navier system. The Clifford algebra language allows us to rewrite this…

math.FA2013

Infinite product representations for kernels and iterations of functions

D. Alpay, P. Jorgensen, I. Lewkowicz +1

We study infinite products of reproducing kernels with view to their use in dynamics (of iterated function systems), in harmonic analysis, and in stochastic processes. On the way,…