Definable retractions over Henselian valued fields with analytic structure

Abstract

Let $K$ be a Henselian, non-trivially valued field with separated analytic structure. We prove the existence of definable retractions onto an arbitrary closed definable subset of $K^n$. Hence directly follow definable non-Archimedean versions of the extension theorems by Tietze--Urysohn and Dugundji. This generalizes our previous paper dealing with complete non-Archimedean fields with separated power series and remains true for Henselian valued fields with strictly convergent analytic structure, because every such a structure can be extended in a definitional way to a separated analytic structure. Our proof uses a variant of the one from that paper, based on canonical resolution of singularities, and a model-theoretic compactness argument.

arXiv admin note: text overlap with arXiv:1901.00162 Withdrawn because of an essential gap in the model-theoretic compactness argument, which requires a deeper analysis of canonical desingularization from the viewpoint of definability