Polish G-spaces, the generalized model theory and complexity

Abstract

Given Polish space ${\bf Y}$ and continuous language $L$ we study the corresponding logic $\mathsf{Iso}({\bf Y})$-space ${\bf Y}_L$. We build a framework of generalized model theory towards analysis of Borel/algorithmic complexity of subsets of ${\bf Y}^k_L \times (\mathsf{Iso} ({\bf Y})^l$. The paper substantially develops (and corrects) Section 5 of arxiv:1304.5135. The second version is extended by Remark 3.4.