Francois Metayer
State monads in cartesian closed categories are those defined by the familiar adjunction between product and exponential. We investigate the structure of their algebras, and show that the exponential functor is monadic provided the base category is sufficiently regular, and the exponent is a non-empty object.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
We use the general notion of 2-dimensional adjunction with given coherence equations as introduced by MacDonald-Stone, building on earlier work by Gray, to derive coherence equations for a general 2-monad, which we refer to as a lax-Gray monad. The free lax-Gray 2-monad on one object may be regarded as the suspension of a lax 2-dimensional analogue of the simplicial category Delta. We call this analogue Delta LG for lax-Gray Delta. This is analogous to the way that the free 1-monad Mnd (as presented in Schanuel-Street) is a concrete example of the suspension of the simplicial category Delta, d…
We characterize double adjunctions in terms of presheaves and universal squares, and then apply these characterizations to free monads and Eilenberg--Moore objects in double categories. We improve upon our earlier result in "Monads in Double Categories", JPAA 215:6, pages 1174-1197, 2011, to conclude: if a double category with cofolding admits the construction of free monads in its horizontal 2-category, then it also admits the construction of free monads as a double category. We also prove that a double category admits Eilenberg--Moore objects if and only if a certain parameterized presheaf i…
It it shown that geometric morphisms between elementary toposes can be represented as adjunctions between the corresponding categories of locales. These adjunctions are characterised as those that preserve the order enrichment, commute with the double power locale monad and whose right adjoints preserve finite coproduct. They are also characterised as those adjunctions that preserve the order enrichment and commute with both the upper and the lower power locale monads.
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 this structures and monads objects in the 2-category $\Adj_{\R}(Cat)$ is analysed, where these monad objects will correspond to liftings to the category of algebras of Eilenberg-Moore. Second, the equivalence between these structures and a pair consisting of a Eilenberg-Moore lifting and a Kleisli extension is analysed too, according to E. Manes and P. Mulry…
Given an adjoint pair of functors $F,G$, the composite $GF$ naturally gets the structure of a monad. The same monad may arise from many such adjoint pairs of functors, however. Can one describe all of the adjunctions giving rise to a given monad? In this paper we single out a class of adjunctions with especially good properties, and we develop methods for computing all such adjunctions, up to natural equivalence, which give rise to a given monad. To demonstrate these methods, we explicitly compute the finitary homological presentations of the free $A$-module monad on the category of sets, for …
In this article Hopf parametric adjunctions are defined and analysed within the context of the 2-adjunction of the type $\mathbf{Adj}$-$\mathbf{Mnd}$. In order to do so, the definition of adjoint objects in the 2-category of adjunctions and in the 2-category of monads for $Cat$ are revised and characterized. This article finalises with the application of the obtained results on current categorical characterization of Hopf Monads.
Recently, Dotsenko and Tamaroff have shown that a morphism of $T\longrightarrow S$ of monads over a category $\mathscr C$ satisfies the PBW-property if and only if it makes $S$ into a free right $T$-module. We consider an adjunction $Ψ=(G,F)$ between categories $\mathscr C$, $\mathscr D$, a monad $S$ on $\mathscr C$ and a monad $T$ on $\mathscr D$. We show that a morphism $ϕ:(\mathscr C,S)\longrightarrow (\mathscr D,T)$ that is well behaved with respect to the adjunction $Ψ$ has a PBW-property if and only if it makes $S$ satisfy a certain freeness condition with respect to $T$-modules with val…
The 2-Adjunction that relates Universal Arrows and Extensive Monads
本文显式构造了连接万有箭头与广延单子的 2-伴随，该构造基于相应 2-范畴的同构，为 Gray-范畴上的伪伴随与伪单子理论奠定基础，并为计算机科学家提供研究广延单子的工具。
Enriched structure-semantics adjunctions and monad-theory equivalences for subcategories of arities
本文为元数子范畴的充实结构-语义伴随与单子-理论等价发展了公理化框架，同时推广了既有理论并确立了适用于局部有界闭范畴的新示例类。
We use the basic expected properties of the Gray tensor product of $(\infty,2)$-categories to study (co)lax natural transformations. Using results of Riehl-Verity and Zaganidis we identify lax transformations between adjunctions and monads with commutative squares of (monadic) right adjoints. We also identify the colax transformations whose components are equivalences (generalizing the "icons" of Lack) with the 2-morphisms that arise from viewing $(\infty,2)$-categories as simplicial $\infty$-categories. Using this characterization we identify the $\infty$-category of monads on a fixed object …
We extend the basic concepts of Street's formal theory of monads from the setting of 2-categories to that of double categories. In particular, we introduce the double category Mnd(C) of monads in a double category C and define what it means for a double category to admit the construction of free monads. Our main theorem shows that, under some mild conditions, a double category that is a framed bicategory admits the construction of free monads if its horizontal 2-category does. We apply this result to obtain double adjunctions which extend the adjunction between graphs and categories and the ad…
We show how to "interleave" the monad for operads and the monad for contractions on the category \coll of collections, to construct the monad for the operads-with-contraction of Leinster. We first decompose the adjunction for operads and the adjunction for contractions into a chain of adjunctions each of which acts on only one dimension of the underlying globular sets at a time. We then exhibit mutual stability conditions that enable us to alternate the dimension-by-dimension free functors. Hence we give an explicit construction of a left adjoint for the forgetful functor $\owc \lra \coll$, fr…
Generalization of formal monad theory to lax functors
本文通过两种方法将形式幺半群理论推广到松弛函子，定义了松弛教义伴随并证明余反射嵌入，同时推广了Beck分配律刻画定理。
In this paper, we introduce a cofibrant simplicial category that we call the free homotopy coherent adjunction and characterize its n-arrows using a graphical calculus that we develop here. The hom-spaces are appropriately fibrant, indeed are nerves of categories, which indicates that all of the expected coherence equations in each dimension are present. To justify our terminology, we prove that any adjunction of quasi-categories extends to a homotopy coherent adjunction and furthermore that these extensions are homotopically unique in the sense that the relevant spaces of extensions are contr…
Monads on dagger categories
本文研究dagger范畴上的单子理论，证明满足Frobenius定律的dagger单子可分解为伴随且极值解仍具dagger结构，刻画了Frobenius定律的融贯性质及强单子与Frobenius幺半群的关系。
Let $U$ be a strong monoidal functor between monoidal categories. If it has both a left adjoint $L$ and a right adjoint $R$, we show that the pair $(R,L)$ is a linearly distributive functor and $(U,U)\dashv (R,L)$ is a linearly distributive adjunction, if and only if $L\dashv U$ is a Hopf adjunction and $U\dashv R$ is a coHopf adjunction. We give sufficient conditions for a strong monoidal $U$ which is part of a (left) Hopf adjunction $L\dashv U$, to have as right adjoint a twisted version of the left adjoint $L$. In particular, the resulting adjunction will be (left) coHopf. One step further,…
Each distributor between categories enriched over a small quantaloid Q gives rise to two adjunctions between the categories of contravariant and covariant presheaves, and hence to two monads. These two adjunctions are respectively generalizations of Isbell adjunctions and Kan extensions in category theory. It is proved that these two processes are functorial with infomorphisms playing as morphisms between distributors; and that the free cocompletion functor of Q-categories factors through both of these functors.
This chapter describes interrelations between: (1) algebraic structure on sets of scalars, (2) properties of monads associated with such sets of scalars, and (3) structure in categories (esp. Lawvere theories) associated with these monads. These interrelations will be expressed in terms of "triangles of adjunctions", involving for instance various kinds of monoids (non-commutative, commutative, involutive) and semirings as scalars. It will be shown to which kind of monads and categories these algebraic structures correspond via adjunctions.
It is well established that equational algebraic theories, and the monads they generate, can be used to encode computational effects. An important insight of Power and Shkaravska is that comodels of an algebraic theory T -- i.e., models in the opposite category Set^op -- provide a suitable environment for evaluating the computational effects encoded by T. As already noted by Power and Shkaravska, taking comodels yields a functor from accessible monads to accessible comonads on Set. In this paper, we show that this functor is part of an adjunction -- the "costructure-cosemantics adjunction" of …
In this work, we describe an adjunction between the comma category of SET-based monads under the V-powerset monad and the category of associative lax extensions of SET-based monads to the category of V-relations. In the process, we give a general construction of the Kleisli extension of a monad to the category of V-relations.
Given a monad and a comonad, one obtains a distributive law between them from lifts of one through an adjunction for the other. In particular, this yields for any bialgebroid the Yetter-Drinfel'd distributive law between the comonad given by a module coalgebra and the monad given by a comodule algebra. It is this self-dual setting that reproduces the cyclic homology of associative and of Hopf algebras in the monadic framework of Boehm and Stefan. In fact, their approach generates two duplicial objects and morphisms between them which are mutual inverses if and only if the duplicial objects are…
This dissertation is devoted to a study of adjunctions concerning categories enriched over a quantaloid Q (or Q-categories for short), with the following types of adjunctions involved: (1) adjoint functors between Q-categories; (2) adjoint distributors between Q-categories; (3) adjoint functors between categories consisting of Q-categories. For a small quantaloid Q and a distributor between Q-categories, two adjunctions between the Q-categories of contravariant and covariant presheaves are presented. These adjunctions respectively extend the fundamental construction of Isbell adjunctions and K…
We define Hopf monads on an arbitrary monoidal category, extending the definition given previously for monoidal categories with duals. A Hopf monad is a bimonad (or opmonoidal monad) whose fusion operators are invertible. This definition can be formulated in terms of Hopf adjunctions, which are comonoidal adjunctions with an invertibility condition. On a monoidal category with internal Homs, a Hopf monad is a bimonad admitting a left and a right antipode. Hopf monads generalize Hopf algebras to the non-braided setting. They also generalize Hopf algebroids (which are linear Hopf monads on a cat…
This paper provides geometrical descriptions of the Frobenius monad freely generated by a single object. These descriptions are related to results connecting Frobenius algebras and topological quantum field theories. In these descriptions, which are based on coherence results for self-adjunctions (adjunctions where an endofunctor is adjoint to itself), ordinals in epsilon zero play a prominent role. The paper ends by considering how the notion of Frobenius algebra induces the collapse of the hierarchy of ordinals in epsilon zero, and by raising the question of the exact categorial abstraction …
The formal theory of relative monads
本文在 virtual equipment 中建立相对单子与相对伴随的形式理论，并通过表示定理统一 Walters、Diers 及 Altenkirch 等人的相关概念。
Generalizing the approach to pseudo monoidal DG-categories as certain colored non-symmetric DG-operads, we introduce a certain relaxed notion of a category enriched in DG-categories. We construct model structures on the category of colored non-symmetric DG-operads and on the category of DGCat-enriched categories with a fixed set of objects. This allows us to talk about strong homotopy maps in both settings. We discuss the notion of a strong homotopy monad in a DG-category and a notion of strong homotopy adjunction data for two DG-functors.
Given an adjunction connecting reasonable categories with weak equivalences, we define a new derived bar and cobar construction associated to the adjunction. This yields homotopical models of the completion and cocompletion associated to the monad and comonad of the adjunction. We discuss applications of these resolutions to spectral sequences for derived completions and Goodwillie calculus in general model categories.
We show that several apparently unrelated formulas involving left or right Bousfield localizations in homotopy theory are induced by comparison maps associated with pairs of adjoint functors. Such comparison maps are used in the article to discuss the existence of functorial liftings of homotopical localizations and cellularizations to categories of algebras over monads acting on model categories, with emphasis on the cases of module spectra and algebras over simplicial operads. Some of our results hold for algebras up to homotopy as well; for example, if $T$ is the reduced monad associated wi…
It is known that the so-called monadic decomposition, applied to the adjunction connecting the category of bialgebras to the category of vector spaces via the tensor and the primitive functors, returns the usual adjunction between bialgebras and (restricted) Lie algebras. Moreover, in this framework, the notions of augmented monad and combinatorial rank play a central role. In order to set these results into a wider context, we are led to substitute the monadic decomposition by what we call the adjoint decomposition. This construction has the advantage of reducing the computational complexity …
We introduce and study Hopf monads on autonomous categories (i.e., monoidal categories with duals). Hopf monads generalize Hopf algebras to a non-braided (and non-linear) setting. Indeed, any monoidal adjunction between autonomous categories gives rise to a Hopf monad. We extend many fundamental results of the theory of Hopf algebras (such as the decomposition of Hopf modules, the existence of integrals, Maschke's criterium of semisimplicity, etc...) to Hopf monads. We also introduce and study quasitriangular and ribbon Hopf monads (again defined in a non-braided setting).
We investigate the notion of involutive weak globular $ω$-categories via Jacque Penon's approach. In particular, we give the constructions of a free self-dual globular $ω$-magma, of a free strict involutive globular $ω$-category, over an $ω$-globular set, and a contraction between them. The monadic definition of involutive weak globular $ω$-categories is given as usual via algebras for the monad induced by a certain adjunction. In our case, the adjunction is obtained from the "free functor" that associates to every $ω$-globular set the above contraction. Some examples of involutive weak globul…
We explain two related constructions on the data of two monoidal symmetric closed categories $\mathscr{A}$ and $\mathscr{E}$ and monoidal functors $F: \mathscr{E}\to \mathscr{A}$ and $G: \mathscr{A}\to \mathscr{E}$. In a first part, we recall and partly extend work of A. Kock: In case $F$ is left-adjoint to $G$, and this adjunction is monoidal, we can equip the Eilenberg-Moore category $\mathscr{E}^T$ for $T$ being the canonical monad associated to the adjunction, with the structure of symmetric monoidal closed category, provided $\mathscr{E}$ has equalizers and $\mathscr{E}^T$ co-equalizers. …
The notion of "super convex spaces" generalizes the idea of convex spaces by replacing finite affine sums with countable affine sums. Using this notion permits a very elegant approach for analysis of the Giry monad on standard measurable spaces and identifying the $\mathcal{G}$-algebras for that monad. We use Isbell duality and restrict the adjunction $\mathbf{Spec} \dashv \mathcal{O}$ to a proper subcategory of super convex spaces and separated standard measurable spaces.
Dual adjunctions between enriched algebraic categories
该研究在丰富代数理论框架下，将 Freyd 定理推广至代数对偶伴随，建立其与双折叠代数特殊类的双等价，证明丰富代数理论的代数可诱导稳定代数对偶伴随并讨论相关实例。
Consider a monad on an idempotent complete triangulated category with the property that its Eilenberg-Moore category of modules inherits a triangulation. We show that any other triangulated adjunction realizing this monad is 'essentially monadic', i.e. becomes monadic after performing the two evident necessary operations of taking the Verdier quotient by the kernel of the right adjoint and idempotent completion. In this sense, the monad itself is 'intrinsically monadic'. It follows that for any highly structured ring spectrum, its category of homotopy (a.k.a. naive) modules is triangulated if …
An Adjunction Between Boolean Algebras and a Subcategory of Stone Algebras
本文研究带有特殊元素$e$且满足$e \ o x = \ eg \ eg x$的Stone代数，并在其范畴与布尔代数范畴之间建立了伴随关系。
The Formal Theory of Monads, Univalently
在单值基础中发展单子的形式理论，定义单子的双范畴并证明其单值性，定义Eilenberg-Moore对象并关联单子与伴随，用Coq和UniMath库形式化。
Given Gray-categories $P$ and $L$, there is a Gray-category $\mathrm{Tricat}_{\mathrm{ls}}(P,L)$ of locally strict trihomomorphisms with domain $P$ and codomain $L$, tritransformations, trimodifications, and perturbations. If the domain $P$ is small and the codomain $L$ is cocomplete, we show that this Gray-category is isomorphic as a Gray-category to the Gray-category $\mathrm{Ps}$-$T$-$\mathrm{Alg}$ of pseudo algebras, pseudo functors, transformations, and modifications for a Gray-monad $T$ derived from left Kan extension. Inspired by a similar situation in two-dimensional monad theory, we a…
For an associative ring $R$, let $P$ be an $R$-module with $S=\End_R(P)$. C.\ Menini and A. Orsatti posed the question of when the related functor $\Hom_R(P,-)$ (with left adjoint $P\ot_S-$) induces an equivalence between a subcategory of $_R\M$ closed under factor modules and a subcategory of $_S\M$ closed under submodules. They observed that this is precisely the case if the unit of the adjunction is an epimorphism and the counit is a monomorphism. A module $P$ inducing these properties is called a $\star$-module. The purpose of this paper is to consider the corresponding question for a func…
Lax comma $2$-categories and admissible $2$-functors
本文开展Janelidze-Galois理论的二维扩展研究，提出松弛幂等语境下的2-容许2-函子概念，研究松弛逗号2-范畴性质，证明相关2-伴随诱导关系并给出充分条件与实例，最后关联余等化子与Kan扩张。
We construct a factorization of the Giry monad through the category of convex spaces, and show that, provided that no measurable cardinals exist, probability measures can be viewed as natural transformations. Using the adjunction of this factorization, we then show the category of Giry algebras is equivalent to the category of convex measurable spaces where the $σ$-algebra structure associated with a convex space satisfies an elementary property.
A duality between monads and monadic morphisms
本文在任意$(\infty,2)$-范畴中建立单调子与单调态射之间的对偶性，并在多种示例中刻画单调态射，统一了若干代数结构与其表示之间的对偶性，并提供将结构从单调子转移到其$\infty$-范畴的机制。
Generalized multicategories: change-of-base, embedding, and descent
本文在广义多范畴之间构造并研究了一个伴随对，证明了左伴随的完全忠实性与拉回保持性，并将其应用于广义富集多范畴结构的下降理论。
A dagger category is a category equipped with a functorial way of reversing morphisms, i.e. a contravariant involutive identity-on-objects endofunctor. Dagger categories with additional structure have been studied under different names e.g. in categorical quantum mechanics and algebraic field theory. In this thesis we study the dagger in its own right and show how basic category theory adapts to dagger categories. We develop a notion of a dagger limit that we show is suitable in the following ways: it subsumes special cases known from the literature; dagger limits are unique up to unitary isom…
Finitary monads on $\mathsf{Pos}$ are characterized as the precisely the free-algebra monads of varieties of algebras. These are classes of ordered algebras specified by inequations in context. Analagously, finitary enriched monads on $\mathsf{Pos}$ are characterized: here we work with varieties of coherent algebras which means that their operations are monotone.
Sifted Colimits, Strongly Finitary Monads and Continuous Algebras
本文刻画了 Pos、CPO 和 DCPO 范畴上强有限单子等价于保持筛选余极限的单子，并将连续代数簇等同于强有限单子的单子范畴。
Firm Frobenius algebras are firm algebras and counital coalgebras such that the comultiplication is a bimodule map. They are investigated by categorical methods based on a study of adjunctions and lifted functors. Their categories of comodules and of firm modules are shown to be isomorphic if and only if a canonical comparison functor from the category of comodules to the category of non-unital modules factorizes through the category of firm modules. This happens for example if the underlying algebra possesses local units, e.g. the firm Frobenius algebra arises from a co-Frobenius coalgebra ov…
Stone Duality for Monads
本文研究了单调子的石对偶性，通过构造一个反变的幂等伴随，将有等级的单调子范畴与内部范畴和内部反函子范畴联系起来，揭示了单调子的行为范畴与局部范畴之间的对应关系。
The bounded ideal monad on the category of quasi-metric spaces and its algebras
本研究为拟度量空间引入有界理想概念，构造了拟度量空间范畴上的有界理想单子，刻画了其代数与连续代数的结构，建立了度量结构与序结构的联系。
It is well known that classical varieties of $Σ$-algebras correspond bijectively to finitary monads on $\mathsf{Set}$. We present an analogous result for varieties of ordered $Σ$-algebras, i.e., classes presented by inequations between $Σ$-terms. We prove that they correspond bijectively to strongly finitary monads on $\mathsf{Pos}$. That is, those finitary monads which preserve reflexive coinserters. We deduce that strongly finitary monads have a coinserter presentation, analogous to the coequaliser presentation of finitary monads due to Kelly and Power. We also show that these monads are lif…
In earlier work, Batanin has shown that an important class of definitions of higher categories could be apprehended together simply as monads over globular sets. This allowed him to generalize the notion of polygraph, initially introduced by Street and Burroni for strict categories, to all algebraic globular higher categories. In this work, we refine this perspective and introduce new constructions and properties for this class of higher categories. In particular, we define the notion of cellular extension and its associated free construction, from which we obtain another definition of polygra…
For finitary regular monads T on locally finitely presentable categories we characterize the finitely presentable objects in the category of T-algebras in the style known from general algebra: they are precisely the algebras presentable by finitely many generators and finitely many relations.
Strongly finitary metric monads are too strong
该研究指出强有限度量单子过于强大，通过反例证明自由代数单子并非全部强有限，并揭示了1-基本单子的特性。
The nerve theorem for relative monads
本文为具有稠密根的充实相对单子建立了代数范畴的刻画定理，推广了现有神经定理，并在精确虚拟装备背景下揭示了相对单子与其松散单子通过双范畴极限构造代数对象的关系。
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.
$A_{\infty}$-structures in monoidal DG categories and strong homotopy unitality
本文在任意幺半DG范畴中借助无界扭曲复形定义A∞代数、余代数、模与余模，引入强同伦幺性，构造自由-遗忘同伦伴随及导出范畴，并证明A∞代数与余代数的同伦伴随给出导出模-余模等价，应用于A∞单子与增强正合单子。
It is well-known that the category of Kleisli algebras for a monoidal monad carries a canonical monoidal structure. We define the notion of a commutative graded monad and present a strictly two-categorical proof that Kleisli algebras for such monads equally carry a canonical monoidal structure which reduce to the monoidal monad case when the commutative graded monad in question is graded over the trivial monoidal category.
Categories meet semigroups in various ways
本文研究半群与范畴论的交汇，建立带选定箭头范畴与半群的伴随关系，用Karoubi包络分解刻画正则半群，还探究了半群单子的映射及性质保持问题。
Ultracategories as colax algebras for a pseudo-monad on CAT
该研究证明Shulman的猜想，即Lurie定义的超范畴是CAT上某伪monad的正规余 lax代数，左右超函子对应lax/余 lax代数态射，为超范畴研究提供代数视角。
Generalising the well-known correspondence between two-sided adjunctions and Frobenius algebras, we establish a one-to-one correspondence between local adjunctions of C*-correspondences, as defined and studied in prior work with P. Clare and N. Higson; and Frobenius C*-algebras, a natural C*-algebraic adaptation of the standard notion of Frobenius algebras that we introduce here.
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。