Let X$X$ be a compact Riemann surface and G = Aut(X)$G = Aut(X)$ be its group of automorphisms (biholomorphisms between X$X$ and X$X$). We know GIt is known that $G$ acts on the space Harm(X)$Harm(X)$ of all harmonic forms and also on the space Omega(X)$Omega(X)$ of all holomorphic forms.
We know that Harm(X)$Harm(X)$ is a direct sum of Omega(X)$Omega(X)$ and its conjugate.
Now, if we know the representation of G$G$ on Harm(X)$Harm(X)$ (by this I mean we have a matrix for each element of G$G$), how can we find matrices for the representation of G$G$ on Omega(X)?$Omega(X)\ ?$
ADDED: I am assuming we have no information about Omega(X)$Omega(X)$ or Harm(X)$Harm(X)$. We just know the genus of X$X$, G$G$ (with a multiplication table) and the representation of G$G$ on Harm(X)$Harm(X)$ (the matrices associated to each element of the group).