Fred W. Helenius

My dissertation research concerns the Lie algebras of algebraic groups, their root systems, and related nonassociative algebra structures (such as Freudenthal triple systems).

A draft preprint of an article describing my research is now available; the title is "Freudenthal triple systems by root system methods".

Here are the slides from my presentation at the January 2009 Joint Mathematics Meetings, which is likewise called "Freudenthal Triple Systems by Root System Methods".

My dissertation defense was on 4 May 2009. The more extensive slides for that event have the subtly different title "Freudenthal Triple Systems via Root System Methods", which is my actual dissertation title.

The dissertation itself is now available through Emory's Electronic Theses and Dissertations system.

[The picture on the right shows the root system of the Lie algebra B₃.]

I'm also interested in number theory. Here are some links to web pages related to problems I've worked on:

Achim Flammenkamp's list of multiperfect numbers.

A list of solutions to the equation phi(sigma(n)) = n.

My presentation at the December 2006 ACES Workshop, which was called "Finiteness of the Class Group à la Dedekind".

Browse through my contributions to the Online Encyclopedia of Integer Sequences.