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- Gert J. Heckman, E . M . Opdam
- 2013

- Gert J. Heckman, Eduard Looijenga, EDUARD LOOIJENGA
- 2008

To Tonny Springer for his 75th birthday

Consider a complex projective space with its Fubini-Study metric. We study certain one parameter deformations of this metric on the complement of an arrangement (= finite union of hyperplanes) whose Levi-Civita connection is of Dunkl type. Interesting examples are obtained from the arrangements defined by finite complex reflection groups. We determine a… (More)

- Maris van Haandel, Gert J. Heckman
- 2008

We present a natural proof of Kepler’s law of ellipses in the spirit of Euclidean geometry. Moreover we discuss two existing Euclidean geometric proofs, one by Feynman in hist Lost Lecture from 1964 and the other by Newton in the Principia of 1687.

These are expanded notes from a set of lectures given at the school “Actions Hamiltoniennes: leurs invariants et classification” at Luminy in April 2009. The topics center around the theorem of Kempf and Ness [58], which describes the equivalence between the notion of quotient in geometric invariant theory introduced by Mumford in the 1960’s [80], and the… (More)

- Gert J. Heckman, Maarten van Pruijssen
- 2017

In this paper we study matrix valued orthogonal polynomials of one variable associated with a compact connected Gelfand pair (G,K) of rank one, as a generalization of earlier work by Koornwinder [29] and subsequently by Koelink, van Pruijssen and Roman [27], [28] for the pair (SU(2) × SU(2), SU(2)), and by Grünbaum, Pacharoni and Tirao [13] for the pair… (More)

- Gert J. Heckman
- 2017

- Gert J. Heckman, Tim de Laat
- 2017

- Wim Couwenberg, Gert J. Heckman, EDUARD LOOIJENGA
- 2017

We discuss a special eigenstate of the quantized periodic Calogero Moser system associated to a root system. This state has the property that its eigenfunctions, when regarded as multivalued functions on the space of regular conjugacy classes in the corresponding semisimple complex Lie group, trans form under monodromy according to the complex reflection… (More)

- Jesse J. Heckman, Rémi Proville, Gert J. Heckman, Alireza Azarfar, Tansu Celikel, Bernhard Englitz
- Scientific reports
- 2017

Mice display a wide repertoire of vocalizations that varies with age, sex, and context. Especially during courtship, mice emit ultrasonic vocalizations (USVs) of high complexity, whose detailed structure is poorly understood. As animals of both sexes vocalize, the study of social vocalizations requires attributing single USVs to individuals. The… (More)