Visualizing Lie Subalgebras
using Root and Weight Diagrams

Aaron Wangberg

Department of Mathematics
Winona State University University
Winona, MN 55987

awangberg@winona.edu

Tevian Dray

Department of Mathematics
Oregon State University
Corvallis, OR 97331

tevian@math.oregonstate.edu

Abstract

While Dynkin diagrams are useful for classifying Lie algebras, it is the root and weight diagrams that are most often used in applications, such as when describing the properties of fundamental particles. This paper illustrates how to construct root and weight diagrams from Dynkin diagrams, and how the root and weight diagrams can be used to identify subalgebras. In particular, we show how this can be done for some algebras whose root and weight diagrams have dimension greater than $3$, including the exceptional Lie algebras $F_4$ and $E_6$.

Contents

1. Introduction
2. Root and Weight Diagrams of Lie Algebras
3. Subalgebras of Algebras
4. Applications to Algebras of Dimension Greater than $3$
5. Conclusion
6. References