3 papers
math.LO2026
Chains and antichains in the Weihrauch lattice
Steffen Lempp, Alberto Marcone, Manlio Valenti
We study the existence and the distribution of "long" chains in the Weihrauch degrees, mostly focusing on chains with uncountable cofinality. We characterize when such chains have…
math.LO2025
The Borel complexity of the class of models of first-order theories
Uri Andrews, David Gonzalez, Steffen Lempp +2
We investigate the descriptive complexity of the set of models of first-order theories. Using classical results of Knight and Solovay, we give a sharp condition for complete theori…
math.LO2024
A jump operator on the Weihrauch degrees
Uri Andrews, Steffen Lempp, Alberto Marcone +2
A partial order admits a jump operator if there is a map that is strictly increasing and weakly monotone. Despite its name, the jump in the Weihrauch la…