J. Liesen

activity

20122026

most citedA framework for deflated and augmented Krylov subspace methods

74 citations · 255 across the 21 of their papers we have counts for

collaborators

Showing 2014Show all

3 papers · 1 filter

math.CV2014★ 13 cited

A Note on the Maximum Number of Zeros of $r (z) - z ˉ$

Robert Luce, Olivier Sète, Jörg Liesen

An important theorem of Khavinson & Neumann (Proc. Amer. Math. Soc. 134(4), 2006) states that the complex harmonic function $r (z) - z ˉ$ , where $r$ is a rational function of de…

astro-ph.IM2014★ 12 cited

Creating images by adding masses to gravitational point lenses

Olivier Sète, Robert Luce, Jörg Liesen

A well-studied maximal gravitational point lens construction of S. H. Rhie produces $5 n$ images of a light source using $n + 1$ deflector masses. The construction arises from a circu…

math.CV2014★ 17 cited

Perturbing rational harmonic functions by poles

Olivier Sète, Robert Luce, Jörg Liesen

We study how adding certain poles to rational harmonic functions of the form $R (z) - z ˉ$ , with $R (z)$ rational and of degree $d \geq 2$ , affects the number of zeros of the result…

A Note on the Maximum Number of Zeros of r(z)−zˉ

Creating images by adding masses to gravitational point lenses

Perturbing rational harmonic functions by poles

A Note on the Maximum Number of Zeros of $r (z) - z ˉ$