Tagged Questions
1
vote
0answers
22 views
Description of certain invariant polynomials (not a group action)
Working on a recent question led me to the following invariant-computation problem : let
$$
A=\bigg\lbrace P \in {\mathbb Q}[X_1,X_2,X_3,X_4] \ \bigg| \\ \quad\
P(X_1X_3+X_2X_4+X_1X_4,\ X_2X_3,\ ...
3
votes
3answers
91 views
Ring of invariants of Klein Four group
Assume $F$ is a field and assume $f\in F[x_1,\ldots,x_4]$ is a polynomial that is invariant under the Klein Four group $V_4$. How can I show that this polynomial can then be rewritten as a polynomial ...
2
votes
1answer
71 views
Describe invariant polynomials under action of commutative group of order eight.
I believe the question below should be fairly standard in invariant theory ; I hope someone more familiar with it than me can explain a bit more or point to a reference.
Let $F$ be polynomial field ...
