Papers

Reconstructing global fields from Dirichlet L-series [arxiv] (with Cornelissen, Li, Marcolli, Smit)

Standard models of finite fields (with Hendrik Lenstra), chapter in: Handbook of Finite Fields

Index formulae for integral Galois modules [arxiv] (with Alex Bartel), to appear in the Journal of the LMS

Inverse Problems for deformation rings [arxiv] (with Frauke Bleher, Ted Chinburg), to appear in TAMS.

Isospectral surfaces with distinct covering spectra via Cayley Graphs [arxiv] (with Ruth Gornet, Craig J. Sutton) Geometriae Dedicata , Volume 158, Issue 1 (2012), Page 343-352

The valuation criterion for normal basis generators (with Mathieu Florence, Lara Thomas), Bull. London Math. Soc (2012) 44 (4): 729-737

Lambda actions of rings of integers [arxiv] (with Jim Borger), 2011

Sunada's method and the covering spectrum [arXiv],
J. Differential Geom. 86 (2010), no. 3, 501-537 Maximal Lambda-orders over Z (with Jim Borger), Bull. London Math. Soc. 2008 40(3):439-446;

Local Galois module structure in positive characteristic and continued fractions (with Lara Thomas), Archiv der Mathematik 88 no. 3 (2007),

Reken mee met ABC (with Gillien Geuze),
Nieuw Archief voor Wiskunde (5th series) 8 (2007), 26-30; see Update.

The Droste-effect and the exponential transform
pp. 169-178 in: Renaissance Banff, Bridges: Mathematical Connections in Art, Music and Science, Proceedings 2005.

Relations between jacobians of modular curves of level p² (with I. Chen and M. Grabitz)
J. Théor. Nombres Bordeaux 16 (2004) 95−106

On arithmetically equivalent fields with distinct p-class numbers
Journal of Algebra 272 (2004), 417-424.

The mathematical structure of Escher's Print Gallery (with H.W. Lenstra)
Notices of the Amer.Math.Soc. 50 no. 4 (2003), 446-451.

On arithmetically equivalent number fields of small degree (with W. Bosma)
in: C. Fieker, D. Kohel (Eds.), Algorithmic Number Theory (Proc. ANTS V, Sydney),
Lecture Notes in Computer Science 2369, Springer-Verlag 2002.

A computational approach to class number relations [PDF] (with W. Bosma)
J. Symbolic Comput. 31 (2001), 97-112.

Brauer-Kuroda relations for S-class numbers [PDF]
Acta Arith. 98 no. 2 (2001) 133-146.

The cyclic subfield integer index [PDF]
J. Théor. Nombres Bordeaux 12 (2000), 209-218

Sur un résultat d'Imin Chen [PS] (with B. Edixhoven)
Mathematical Research Letters 7 (2000), 147-154

Linearly equivalent actions of solvable groups [PS], (with H.W. Lenstra)
Journal of Algebra 228 (2000), 270-285

Generating arithmetically equivalent number fields with elliptic curves, [PDF]
in: J.P. Buhler (Ed.), Algorithmic Number Theory Lecture Notes in Computer Science 1423, Springer-Verlag 1998. (Proc. ANTS III, Portland Oregon).

Criteria for complete intersections, [PDF] (with K. Rubin and R. Schoof)
In: Modular Forms and Fermat's Last Theorem, Springer-Verlag 1997.
(Proc. Boston Conference on Wiles's proof of Fermat's Last Theorem, Eds. Cornell, Silverman, Stevens)

Explicit construction of universal deformation rings [PDF]; (with H.W. Lenstra),
In: Modular Forms and Fermat's Last Theorem, Springer-Verlag 1997.
(Proc. Boston Conference on Wiles's proof of Fermat's Last Theorem, Eds. Cornell, Silverman, Stevens)

A differential criterion for complete intersections [PDF]
Collect. Math. 48, 1-2 (1997), 85-96.
(Proc. Journeés Arithmetiques 1995)

Finite complete intersection algebras and the completeness radical,, with H.W. Lenstra, Jr., [PDF]
J. Algebra 196 (1997) 520-531.

The different and differentials for local fields with imperfect residue fields, [PDF]
Proc. Edinburgh Math. Soc. 40 (1997), 353-365.

Factor equivalence results for integers and units, [PDF]
Enseign. Math. (2) 42 (1996) 383-394.

On a conductor discriminant formula of McCulloh,
Illinois J. Math. 40 (1996) No 2, 338-343.

Measure characteristics of complexes,
Cahiers Topologie Géom. Différentielle Catégoriques 37, no. 1 (1996), 3-20.

Primitive elements in integral bases,
Acta Arith. 71 (1995), 159-170.

Zeta functions do not determine class numbers, with R. Perlis,
Bull. Amer. Math. Soc. (N.S.) 31 (1994), 213-216.

Algebraic numbers with integral power traces,
J. Number Theory 45, No. 1 (1993), 112-116.

Ramification groups of local fields with imperfect residue class fields, [PDF]
J. Number Theory 44, No. 3 (1993), 229-236.

The fundamental group of the Hawaiian earring is not free [PDF]
Internat. J. Algebra Comput. 2, No. 1 (1992), 33-37.