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Lax monoidal powerset-enriched monads yield a monoidal structure on the category of monoids in the Kleisli category of a monad. Exponentiable objects in this category are identified as those Kleisli monoids with algebraic structure. This…

Category Theory · Mathematics 2013-08-08 Dirk Hofmann , Frédéric Mynard , Gavin J. Seal

We introduce a contravariant idempotent adjunction between (i) the category of ranked monads on $\mathsf{Set}$; and (ii) the category of internal categories and internal retrofunctors in the category of locales. The left adjoint takes a…

Logic in Computer Science · Computer Science 2026-05-20 Richard Garner , Alyssa Renata , Nicolas Wu

In this paper we give a review of the most general approach to description of reference frames, the monad formalism. This approach is explicitly general covariant at each step, permitting to use abstract representation of tensor quantities;…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Nikolai V. Mitskievich

The category of all monads over many-sorted sets (and over other "set-like" categories) is proved to have coequalizers and strong cointersections. And a general diagram has a colimit whenever all the monads involved preserve monomorphisms…

Logic in Computer Science · Computer Science 2014-09-15 Jiří Adámek

We study the concept of idempotence for relative monads, which exhibits several subtleties not present for non-relative monads. In particular, there is a bifurcation of notions of idempotence in the relative setting, which are…

Category Theory · Mathematics 2025-09-10 Nathanael Arkor , Andrew Slattery

Relative monads provide a controlled view of computation. We generalise the monadic metalanguage to a relative setting and give a complete semantics with strong relative monads. Adopting this perspective, we generalise two existing program…

Programming Languages · Computer Science 2025-12-15 Jack Liell-Cock , Zev Shirazi , Sam Staton

We construct explicitly the weights on the simplicial category so that the colimits and limits of 2-functors with those weights provide the Kleisli objects and the Eilenberg-Moore objects, respectively, in any 2-category.

Category Theory · Mathematics 2011-01-04 Marek Zawadowski

In this article, the author analyses distributive and mixed distributive laws and some of their equivalences through the use of 2-adjunctions of the type $\Adj$-$\Mnd$. As far as the distributive laws are concerned, the equivalence between…

Category Theory · Mathematics 2017-06-12 Adrian Vazquez-Marquez

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

We consider representations of quivers taking values in monads or comonads over a Grothendieck category $\mathcal C$. We treat these as scheme like objects whose ``structure sheaf'' consists of monads or comonads. By using systems of…

Category Theory · Mathematics 2025-08-15 Divya Ahuja , Abhishek Banerjee , Surjeet Kour , Samarpita Ray

In this article the 2-adjunction that relates universal arrows and extensive monads is constructed explicitly. This 2-adjunction resembles the one that relates adjunctions and monads since the 2-category of universal arrows is isomorphic to…

Category Theory · Mathematics 2025-02-26 Adrian Vazquez-Marquez , Jenylin Zuniga-Apipilhuasco

We show how the relatively initial or relatively terminal fixed points for a well-behaved functor $F$ form a pair of adjoint functors between $F$-coalgebras and $F$-algebras. We use the language of locally presentable categories to find…

Category Theory · Mathematics 2025-09-03 Ezra Schoen , Jade Master , Clemens Kupke

We introduce a category-theoreticabstraction of a syntax with auxiliary functions, called an admissiblemonad morphism. Relying on an abstract form of structural recursion,we then design generic tools to construct admissible monad…

Logic in Computer Science · Computer Science 2022-04-11 Tom Hirschowitz , Ambroise Lafont

One way of interpreting a left Kan extension is as taking a kind of "partial colimit", whereby one replaces parts of a diagram by their colimits. We make this intuition precise by means of the "partial evaluations" sitting in the so-called…

Category Theory · Mathematics 2024-04-15 Paolo Perrone , Walter Tholen

We generalize the correspondence between theories and monads with arities of arXiv:1101.3064 to $\infty$-categories. Additionally, we introduce the notion of complete theories that is unique to the $\infty$-categorical case and provide a…

Category Theory · Mathematics 2021-06-01 Roman Kositsyn

For functors $L:\A\to \B$ and $R:\B\to \A$ between any categories $\A$ and $\B$, a {\em pairing} is defined by maps, natural in $A\in \A$ and $B\in \B$, $$\xymatrix{\Mor_\B (L(A),B) \ar@<0.5ex>[r]^{\alpha} & \Mor_\A…

Category Theory · Mathematics 2012-05-30 Robert Wisbauer

Monads are of interest both in semantics and in higher dimensional algebra. It turns out that the idea behind usual notion finitary monads (whose values on all sets can be computed from their values on finite sets) extends to a more general…

Category Theory · Mathematics 2012-01-18 Charles Grellois

In this article we describe properties of the 2-functor from the 2-category of comonads to the 2-category of functors that sends a comonad to its forgetful functor. This allows us to describe contexts where algebras over a monad are…

Category Theory · Mathematics 2022-05-04 Brice Le Grignou

In The factorization of the Giry monad (arXiv:1707.00488v2) the author asserts that the category of convex spaces is equivalent to the category of Eilenberg-Moore algebras over the Giry monad. Some of the statements employed in the proof of…

Category Theory · Mathematics 2020-09-15 Tomas Crhak

We consider the terminal monad among those preserving the objects of a subcategory, and in particular preserving the image of a monad. Several common monads are shown to be uniquely characterized by the property of being terminal objects in…

Category Theory · Mathematics 2025-05-20 Emmanuel Dror Farjoun , Sergei O. Ivanov