Publications (10)
Computing graph gonality is hard
Dion Gijswijt, Harry Smit, Marieke van der Wegen
There are several notions of gonality for graphs. The divisorial gonality dgon(G) of a graph G is the smallest degree of a divisor of positive rank in the sense of Baker-Norine. Th…
L-series and isomorphisms of number fields
Harry Smit
Two number fields with equal Dedekind zeta function are not necessarily isomorphic. However, if the number fields have equal sets of Dirichlet -series then they \emph{are} isomo…
Ideal classes of orders in quaternion algebras
Stefano Marseglia, Harry Smit
We provide an algorithm that, given any order in a quaternion algebra over a global field, computes representatives of all right equivalence classes of right -ideals, includ…
Reconstructing global fields from dynamics in the abelianized Galois group
Gunther Cornelissen, Xin Li, Matilde Marcolli +1
We study a dynamical system induced by the Artin reciprocity map for a global field. We translate the conjugacy of such dynamical systems into various arithmetical properties that…
Constructing Tree Decompositions of Graphs with Bounded Gonality
Hans L. Bodlaender, Josse van Dobben de Bruyn, Dion Gijswijt +1
In this paper, we give a constructive proof of the fact that the treewidth of a graph is at most its divisorial gonality. The proof gives a polynomial time algorithm to construct a…
L-series and isogenies of abelian varieties
Harry Smit
Faltings's isogeny theorem states that two abelian varieties are isogenous over a number field precisely when the characteristic polynomials of the reductions at almost all prime i…
L-series and homomorphisms of number fields
Harry Smit
While the zeta function does not determine a number field uniquely, the -series of a well-chosen Dirichlet character does. Moreover, isomorphisms between two number fields are i…
Discrete and metric divisorial gonality can be different
Josse van Dobben de Bruyn, Harry Smit, Marieke van der Wegen
This paper compares the divisorial gonality of a finite graph to the divisorial gonality of the associated metric graph with unit lengths. We show that $\tex…
The -rank of class groups of
Peter Koymans, Adam Morgan, Harry Smit
Let be a quadratic extension. In this paper we study the -rank of the class group , where varies over squarefree rational integers. We…
Reconstructing global fields from Dirichlet L-series
Gunther Cornelissen, Bart de Smit, Xin Li +2
We prove that two global fields are isomorphic if and only if there is an isomorphism of groups of Dirichlet characters that preserves L-series.