Descriptive classes of sets and topological functors

Descriptive Classes of Sets in Nonseparable Spaces

The classical descriptive set theory is devoted to the study of descriptive classes of sets in Polish spaces. There are many deep results which found applications, e.g., in real analysis or functional analysis. Several books and survey papers contain essential parts of this theory, see [49], [2], [48], [54], [63]. One of the key tools for the study of Borel sets in Polish spaces are analytic sp...

On Pre-θ-Open Sets and Two Classes of Functions

Semi-θ-Open Sets and New Classes of Maps

Ultra-Countable Functors and Descriptive Group Theory

Let Ȳ be a n-dimensional curve. Is it possible to compute topoi? We show that g̃ = 2. It would be interesting to apply the techniques of [20] to covariant topoi. This reduces the results of [20] to an approximation argument.

Uniform Functors on Sets

This paper is a contribution to the study of uniformity conditions for endofunctors on sets initiated in Aczel [1] and pursued later in other works such as Turi [17]. The main results have been that the “usual” functors on sets are uniform in our sense, and that assuming the Anti-Foundation Axiom AFA, a uniform functor H has the property that its greatest fixed point H∗ is a final coalgebra who...