# Brandeis University Everyperson Seminar

## Monday November 15, 2004, 4 PM, Goldsmith 317

### tea at
3:30 PM at the Math Department lounge (Goldsmith 300)

**Speaker**: Dylan Thurston (Harvard)

**Title**: The Exceptional Series and Magic Triangle of Lie
Algebras

**Abstract**: Cvitanovic in 1977 and Deligne in 1996 independently
discovered commonalities among all the exceptional Lie algebras, forming
a kind of "series" analogous to the classical *sl(n)* and *o(n)* series;
Deligne conjectured that this series can be extended to a family
depending on a continuous (!) parameter, specializing to the exceptional
Lie algebras at the known points. Cvitanovic furthermore fit these
series into a Magic Triangle, extending Freudenthal's Magic Square.
Following Deligne and Gross, we clarify where this Magic Triangle comes
from and investigate whether several rows have more points on them; this
further extends the Magic Triangle to include some super Lie algebras.