5 papers · 1 filter
Computable Bases
Vasco Brattka, Emmanuel Rauzy
In computable analysis typically topological spaces with countable bases are considered. The Theorem of Kreitz-Weihrauch implies that the subbase representation of a second-countab…
Computability of the Hahn-Banach Theorem Revisited
Vasco Brattka, Christopher Sorg
Computational properties of the Hahn-Banach theorem have been studied in computable, constructive and reverse mathematics and in all these approaches the theorem is equivalent to w…
Uniform Computability of PAC Learning
Vasco Brattka, Guillaume Chirache
We study uniform computability properties of PAC learning using Weihrauch complexity. We focus on closed concept classes, which are either represented by positive, by negative or b…
Effective bases and notions of effective second countability in computable analysis
Vasco Brattka, Emmanuel Rauzy
We investigate different notions of "computable topological base" for represented spaces. We show that several non-equivalent notions of bases become equivalent when we consider co…
Loops, Inverse Limits and Non-Determinism
Vasco Brattka
We introduce an operator on problems in Weihrauch complexity, which we call the inverse limit, and which corresponds to an infinite compositional product. This operation arises nat…