This item is brought to you by Swansea University. Any person downloading material is agreeing to abide by the terms of the repository licence. Copies of full text items may be used or reproduced inâ€¦ (More)

We study closed choice principles for different spaces. Given information about what does not constitute a solution, closed choice determines a solution. We show that with closed choice one canâ€¦ (More)

Represented spaces form the general setting for the study of computability derived from Turing machines. As such, they are the basic entities for endeavors such as computable analysis or computableâ€¦ (More)

Non-deterministic type-2 machines (NDTMs) were suggested by Ziegler [34, 35, 33] as a model for hypercomputation in computable analysis. As demonstrated by Brattka, de Brecht and Pauly [2, 6], theâ€¦ (More)

We investigate the Weihrauch-degree of several solution concepts from noncooperative game theory. While the consideration of Nash equilibria forms the core of our work, also pure and correlatedâ€¦ (More)

We study the computational content of the Brouwer Fixed Point Theorem in the Weihrauch lattice. Connected choice is the operation that finds a point in a non-empty connected closed set given byâ€¦ (More)

We answer a question [2] by Vasco Brattka and Guido Gherardi by proving that the Weihrauch lattice is not a Brouwer algebra. The computable Weihrauch lattice is also not a Heyting algebra, but theâ€¦ (More)

We propose to extend descriptive set theory (DST) beyond its traditional setting of Polish spaces to the represented spaces. There, we can reformulate DST in terms of endofunctors on the categoriesâ€¦ (More)

We investigate choice principles in the Weihrauch lattice for finite sets on the one hand, and convex sets on the other hand. Increasing cardinality and increasing dimension both correspond toâ€¦ (More)