Symmetric products of Galois-Maximal varieties

The main result of this paper is the proof that all the symmetric products of a (finite) Galois-Maximal space are also Galois-Maximal spaces. This applies to the special case of real algebraic varieties, solving the problem first stated by Biswas and D'Mello in \cite{biswas&d'mello:symmetric_products_M-curves} about symmetric products of Maximal curves, and then generalised by Baird in \cite{baird:symmetric_products_GM-curves} to Galois-Maximal curves. We also give characterisations of these spaces and state a new definition that generalises to a larger class of spaces. Then, we extend the characterisation in terms of the Borel cohomology given in \cite{us} to the new family. Finally, we introduce the notion of cohomological stability and cohomological splitting, provide a systematic treatment and relate them with the properties of being a Maximal or Galois-Maximal space. These cohomological properties play an important role in the proof of our main theorem.