4 papers
Defective dual varieties for real spectra
Jens Forsgård
We introduce an invariant of a finite point configuration which we denote the cuspidal form of . We use this invariant to extend Esterov's character…
On transformations of A-hypergeometric functions
Jens Forsgård, Laura Felicia Matusevich, Aleksandra Sobieska
We propose a systematic study of transformations of -hypergeometric functions. Our approach is to apply changes of variables corresponding to automorphisms of toric rings, to Eu…
On the parametric behavior of A-hypergeometric series
Christine Berkesch Zamaere, Jens Forsgård, Laura Felicia Matusevich
We describe the parametric behavior of the series solutions of an A-hypergeometric system. More precisely, we construct explicit stratifications of the parameter space such that, o…
Tropical multiplier sequences
Jens Forsgård
We prove that the diagonal operator defined by a positive sequence preserves tropical and central indices if and only if the sequence is log-concave. In particular we obtain an ele…