Henri Johnston

Contact Information St John's College Cambridge CB2 1TP United Kingdom Phone (college): +44 1223 766724 Phone (dept): +44 1223 764271 Fax : +44 1223 337720 Email: [my first initial] dot [my last name] at dpmms.cam.ac.uk About me I am fellow and college lecturer in pure mathematics at St. John's College, Cambridge. I was previously stipendiary lecturer in pure maths at St. Hugh's College, Oxford. In August 2007, I finished as a graduate student in the mathematics department at Cornell University. I am originally from Jersey in the Channel Islands. Research My research interests include algebraic number theory and arithmetic geometry, in particular Galois module structure and computational number theory. My advisor was Ravi Ramakrishna and for the 2006-07 academic year, I visited Cornelius Greither at Universität der Bundeswehr München, Germany.

Papers

• (with Nigel P. Byott, James E. Carter and Cornelius Greither) On the restricted Hilbert-Speiser and Leopoldt properties, submitted. [arXiv]
• (with David Burns) A non-abelian Stickelberger theorem, submitted. [pdf]
• (with Cornelius Greither) On totally real Hilbert-Speiser fields of type C_p, Acta Arith. 138 (2009), no. 4, 329-336. [Journal] [arXiv]
• (with Cornelius Greither) Non-existence and splitting theorems for normal integral bases, to appear in Annales de l'Institut Fourier. [arXiv]
• (with Werner Bley) Computing generators of free modules over orders in group algebras, J. Algebra 320 (2008), no. 2, 836-852. [Journal] [arXiv] [MR] [ZB]
• (with Cornelius Greither) Capitulation for locally free class groups of orders of group algebras over number fields, Bull. London Math. Soc. 41 (2009), 541-548. [Journal] [arXiv] [MR] [ZB]
• Relative Galois module structure of rings of integers of absolutely Abelian number fields, J. reine angew. Math. 620 (2008), 85-103. [Journal] [arXiv] [MR] [ZB]
• On the trace map between absolutely Abelian number fields of equal conductor, Acta Arith. 122 (2006), no.1, 63-74. [Journal] [arXiv] [MR] [ZB]

Slides for talks

• Non-existence and splitting theorems for normal integral bases CNTA X, Waterloo, 18th July 2008. [PDF]
• Relative Galois module structure of rings of integers of absolutely Abelian number fields, CNTA IX, Vancouver, 14th July 2006. [PDF]