English
Related papers

Related papers: Codensity and the ultrafilter monad

200 papers

Tensor products of ultrafilters have special combinatorial features closely related to Ramsey's Theorem, making them useful tools in applications. Here we first review their fundamental properties and isolate some new ones, including a…

Combinatorics · Mathematics 2025-06-18 Mauro Di Nasso

The fundamental construction underlying descent theory, the lax descent category, comes with a functor that forgets the descent data. We prove that, in any $2$-category $\mathfrak{A} $ with lax descent objects, the forgetful morphisms…

Category Theory · Mathematics 2021-05-21 Fernando Lucatelli Nunes

A new and extensive formalism is developed for monads and galaxies in non-standard enlargements. It is shown that monads and galaxies can be manipulated using order-preserving and order-reversing set-to-set maps, and that set properties…

Logic · Mathematics 2024-06-12 Niels Charlier , Hans Vernaeve

We compare closed and rigid monoidal categories. Closedness is defined by the tensor product having a right adjoint: the internal hom functor. Rigidity, on the other hand, generalises the duality of finite-dimensional vector spaces. In the…

Category Theory · Mathematics 2026-02-06 Sebastian Halbig , Tony Zorman

We establish a duality between monads and monadic morphisms in any $(\infty,2)$-category and characterize monadic morphisms in a wide class of examples. This duality unifies several dualities between algebraic structures and their…

Category Theory · Mathematics 2026-03-19 Hadrian Heine

The monad of convex sets of probability distributions is a well-known tool for modelling the combination of nondeterministic and probabilistic computational effects. In this work we lift this monad from the category of sets to the category…

Logic in Computer Science · Computer Science 2020-05-18 Matteo Mio , Valeria Vignudelli

In semantics and in programming practice, algebraic concepts such as monads or, essentially equivalently, (large) Lawvere theories are a well-established tool for modelling generic side-effects. An important issue in this context are…

Logic in Computer Science · Computer Science 2015-03-17 Sergey Goncharov , Lutz Schröder

In recent times, there has been a growing interest in a structuralist understanding of probability, measure and integration theory. The present thesis contributes to this programme in three ways. First, we construct a commutative…

Category Theory · Mathematics 2024-04-01 Benedikt Peterseim

This paper contributes to the techniques of topo-algebraic recognition for languages beyond the regular setting as they relate to logic on words. In particular, we provide a general construction on recognisers corresponding to adding one…

Logic in Computer Science · Computer Science 2023-06-22 Mai Gehrke , Daniela Petrisan , Luca Reggio

We show that the set of entries generated by any finite set of doubly stochastic matrices is nowhere dense, in contrast to the cases of stochastic matrices or unitary matrices. In other words, there is no finite universal set of doubly…

Functional Analysis · Mathematics 2021-04-02 Wei Zhan

We present an expository overview of the monoidal structures in the category of linearly compact vector spaces. Bimonoids in this category are the natural duals of infinite-dimensional bialgebras. We classify the relations on words whose…

Combinatorics · Mathematics 2021-08-12 Eric Marberg

We define and study a probability monad on the category of complete metric spaces and short maps. It assigns to each space the space of Radon probability measures on it with finite first moment, equipped with the Kantorovich-Wasserstein…

Probability · Mathematics 2019-03-13 Tobias Fritz , Paolo Perrone

We establish a relative monadicity theorem for relative monads with dense roots in a virtual equipment, specialising to a relative monadicity theorem for enriched relative monads. In particular, for a dense $\mathbb V$-functor $j \colon A…

Category Theory · Mathematics 2024-10-18 Nathanael Arkor , Dylan McDermott

We prove that the opposite of the category of coalgebras for the Vietoris endofunctor on the category of compact Hausdorff spaces is monadic over Set. We deliver an analogous result for the upper, lower and convex Vietoris endofunctors…

Logic · Mathematics 2025-09-17 Marco Abbadini , Ivan Di Liberti

We develop the theory of strong and commutative monads in the 2-dimensional setting of bicategories. This provides a framework for the analysis of effects in many recent models which form bicategories and not categories, such as those based…

Logic in Computer Science · Computer Science 2024-06-12 Hugo Paquet , Philip Saville

We prove that the free algebra functor associated to a symmetric, pseudo commutative 2-monad, from the underlying symmetric monoidal 2-category to the 2-category of algebras and pseudo maps over the 2-monad can be enhanced to a…

Category Theory · Mathematics 2025-09-19 Diego Manco

We prove an abstract Fubini-type theorem in the context of monoidal and enriched category theory, and as a corollary we establish a Fubini theorem for integrals on arbitrary convergence spaces that generalizes (and entails) the classical…

Functional Analysis · Mathematics 2012-10-17 Rory B. B. Lucyshyn-Wright

Idempotent analogues of convexity are introduced. It is proved that the category of algebras for the capacity monad in the category of compacta is isomorphic to the category of $(\max,\min)$-idempotent biconvex compacta and their biaffine…

Category Theory · Mathematics 2011-08-08 Oleh Nykyforchyn , Dušan Repovš

We study polynomial functors over locally cartesian closed categories. After setting up the basic theory, we show how polynomial functors assemble into a double category, in fact a framed bicategory. We show that the free monad on a…

Category Theory · Mathematics 2015-05-13 Nicola Gambino , Joachim Kock

We introduce a candidate for the inner hom for $Dbl^{st}_{lx}$, the category of strict double categories and lax double functors, and characterize a lax double functor into it obtaining a lax double quasi-functor. The latter consists of a…

Category Theory · Mathematics 2023-04-03 Bojana Femić