### Proposition 3.3

Let be a primitive form, and let
its Hessian. Recall that we write
if **F** has a triple root in . Then
- if and only if
**F** has at least a double root
in , and if this is the case all the roots of **F** are in fact in
itself.
- if and only if .
- If and , then if and only if
. If then .
- If then we have the following:
If , then .
If but , then .
If and , then there exists such that
, and then .