Henri Johnston

Contact Information St John's College Cambridge CB2 1TP United Kingdom Phone (college): +44 1223 766724 Phone (dept): +44 1223 765901 Office (college): B8 New Court Office (dept): C2.01 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.

Graduate Course

• Galois Modules

Papers

• (with Andreas Nickel) Noncommutative Fitting invariants and improved annihilation results, preprint. [arXiv]
• (with Werner Bley) Computing generators of free modules over orders in group algebras II, Math. Comp. 80 (2011), 2411-2434. [Journal] [arXiv] [MR] [ZB]
• (with Nigel P. Byott, James E. Carter and Cornelius Greither) On the restricted Hilbert-Speiser and Leopoldt properties, to appear in Illinois Journal of Mathematics. [arXiv]
• (with David Burns) A non-abelian Stickelberger theorem, Compositio Math. 147 (2011), 35-55. [Journal] [arXiv] [MR] [ZB]
• (with Cornelius Greither) On totally real Hilbert-Speiser fields of type C_p, Acta Arith. 138 (2009), no. 4, 329-336. [Journal] [arXiv] [MR] [ZB]
• (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]

Maths Books and Notes

• Online notes of interest to number theorists (and others)
• MathOnline
• Free mathemamatics e-books
• Springerlink (lots of Springer books and articles available online if your university has a subscription)
• Cambridge books online (lots of CUP books online if your university has a subscription)
• MathSciNet (often the easiest way to find electronic versions of maths books online if your university has a subscription; once you have found the review, click on the "book" link).
• Best book price (UK book price comparison website)

Maths Links

• MathOverflow
• Detexify (draw a symbol to get the corresponding latex command)
• Number Theory Web (British mirror)
• Conferences in arithmetic geometry