What's so special about unipotent groups

544 Views Asked by At

Why are they so important?

I see them appear in Lie theory, algebraic geometry, etc.

Can somebody elaborate?

For example, can someone explain why they are such natural groups to consider in algebraic geometry?

1

There are 1 best solutions below

3
On BEST ANSWER

They are solvable groups and there representation theory is by far easier than the general representation theory (Mackey-Clifford-etc.)

In principle, it is sufficient to classify the representations of unipotent groups and reductive groups, in order to classify all the representation in full.

Every lie or algebraic group is a semi direct product of a reductive one and a unipotent one.

Also the reductive subgroups of a reductive group determine to a large extent the representation theory via parabolic induction. This involves necessary understanding the parabolic subgroups, hence the unipotent subgroups.