Papers

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.