2
$\begingroup$

Given a topological group $G$ and a subset $S$ of $G$ that topologically generates it, what are the conditions under which an $n$-dimensional continuous linear representation of $G$ over an algebraically closed topological field $k$ can be constructed once we have specified a collection of degree $n$ polynomials with coefficients in $k$ as the characteristic polynomials of the images of elements of $S$?

In other words, when can a continuous homomorphism $\rho: G \rightarrow GL_n(k)$ be constructed from the data $\{c(\rho (s)) \in k[x]: s \in S\}$ where $c(a)$ is the characteristic polynomial of $a$?

Under which further conditions if any is such a representation uniquely determined? Is there an algorithm for constructing it from the collection of characteristic polynomials?

Finally what if we don't require that $k$ be algebraically closed?

Assuming that $k$ is a field of characteristic 0 would be fine, although I am also interested in the characteristic $p$ case.

$\endgroup$
2
  • $\begingroup$ What does it mean to "specif[y] a degree $n$ characteristic polynomial … for each element of $S$"? (EDIT: Oh, you mean a polynomial that must be satisfied by the image of that element?) In addition to the algebraic closure, it might matter whether or not $k$ has characteristic $0$, so you may want to specify that. $\endgroup$
    – LSpice
    Commented Aug 8, 2020 at 17:49
  • 1
    $\begingroup$ @LSpice, thanks for asking for clarification! I've edited the question to take your comment into account as well as added the continuity condition on the representation which seems natural and necessary. $\endgroup$
    – SHS
    Commented Aug 8, 2020 at 18:06

0

You must log in to answer this question.