Xu Huang
This note explains how dependent sums and products are interpreted by adjoints of the base change functor in a locally cartesian closed category. An effort is made to unpack all the definitions so as to make the concepts more transparent to new learners.
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
Cartesian differential categories come equipped with a differential combinator that formalizes the derivative from multi-variable differential calculus, and also provide the categorical semantics of the differential $λ$-calculus. An important source of examples of Cartesian differential categories are the coKleisli categories of the comonads of differential categories, where the latter concept provides the categorical semantics of differential linear logic. In this paper, we generalize this construction by introducing Cartesian differential comonads, which are precisely the comonads whose coKl…
We show that the category of categories with pullbacks and pullback preserving functors is cartesian closed.
We revisit the definition of Cartesian differential categories, showing that a slightly more general version is useful for a number of reasons. As one application, we show that these general differential categories are comonadic over Cartesian categories, so that every Cartesian category has an associated cofree differential category. We also work out the corresponding results when the categories involved have restriction structure, and show that these categories are closed under splitting restriction idempotents.
In this thesis, we introduce Cartesian double categories, motivated by the work of Carboni, Kelly, Walters, and Wood on Cartesian bicategories. Moving from bicategories to the slightly more generalized notion of double categories allows us to set the whole theory inside the welcoming 2-category of double categories, and to overcome technical problems that were caused by working with left adjoints inside a general bicategory. Cartesian double categories that are also fibrant are of particular interest to us. After describing some important properties of Cartesian and fibrant double categories, …
We prove that every locally Cartesian closed $\infty$-category with subobject classifier has a strict initial object and disjoint and universal binary coproducts.
The existence of adjoints to algebraic functors between categories of models of Lawvere theories follows from finite-product-preservingness surviving left Kan extension. A result along these lines was proved in Appendix 2 of Brian Day's 1970 PhD thesis. His context was categories enriched in a cartesian closed base. A generalization is described here with essentially the same proof. We introduce the notion of cartesian monoidal category in the enriched context. With an advanced viewpoint, we give a result about left extension along a promonoidal module and further related results.
Transposing cartesian and other structure in double categories
本文探讨了双范畴中笛卡尔结构与其他结构的转换，通过建立双范畴与双范畴的联系，证明了具有笛卡尔结构的双范畴下存在笛卡尔双范畴。
Cartesian differential categories were introduced to provide an abstract axiomatization of categories of differentiable functions. The fundamental example is the category whose objects are Euclidean spaces and whose arrows are smooth maps. Tensor differential categories provide the framework for categorical models of differential linear logic. The coKleisli category of any tensor differential category is always a Cartesian differential category. Cartesian differential categories, besides arising in this manner as coKleisli categories, occur in many different and quite independent ways. Thus, i…
Cohomology of Small Cartesian Closed Categories
该研究证明了笛卡儿闭合范畴的奎伦上同调与巴乌斯-维尔斯钦格上同调的同构性，并扩展了此前关于小范畴和具有有限积的小范畴的结果。
Properties and Characterisations of Cofree Cartesian Differential Categories
本文研究余自由笛卡尔微分范畴的刻画问题，提出在不指定基范畴的情况下，利用导数为零的微分常数，通过完备超度量空间和单子代数两种方式对其进行刻画，并探讨了其基本性质。
Cartesian differential categories as skew enriched categories
本文将笛卡尔微分范畴刻画为基于斜幺半范畴的充实范畴，并证明每个小笛卡尔微分范畴可完全保持结构地嵌入由微分模态诱导的范畴，从而解决了该领域的一个公开问题。
The goal of this paper is to prove an equivalence between the $(\infty,2)$-category of cartesian factorization systems of $\infty$-categories and that of pointed cartesian fibrations of $\infty$-categories. This generalizes a similar result known for ordinary categories and sheds some light on the interplay between these two seemingly distant concepts.
On the Cartesian closedness of [0,1]-Cat and some of its subcategories
本文研究了[0,1]-Cat的笛卡儿闭性，并证明其等价于多个子类别的笛卡儿闭性。
Cartesian Gray-Monoidal Double Categories
本文通过引入局部立方Gray范畴和双松弛函子，为对称Gray-幺半群双范畴建立了笛卡尔结构，并利用曲面图给出其简洁表示。
It is proved that equalities between arrows assumed for cartesian categories are maximal in the sense that extending them with any new equality in the language of free cartesian categories collapses a cartesian category into a preorder. An analogous result holds for categories with binary products, which may lack a terminal object. The proof is based on a coherence result for cartesian categories, which is related to model-theoretical methods of normalization.
Cartesian Difference Categories
本文提出笛卡尔差分范畴，作为笛卡尔微分范畴与变化作用模型的桥梁，统一建模光滑函数微分与有限差分，并证明其具有切丛单子结构。
A folklore result in category theory is that a (weakly) Cartesian closed category with finite co-products is distributive. Usually, the proof of this small result is carried on using the fact that the exponential functor is right adjoint to the product functor. And, since functors having a right adjoint preserve co-limits, the result follows immediately. But, when we try to explicitly construct the arrows, things become a bit more involved. In rare cases, it is pretty useful to have the exact arrows that make this isomorphism to hold. The purpose of this note is to develop the explicit proof w…
Lax comma categories: cartesian closedness, extensivity, topologicity, and descent
本文刻画基范畴上 lax 逗号范畴的拓扑性、完备性、外延性、笛卡尔闭性及有效下降条件，并为二维 Janelidze Galois 理论提供基础。
Cartesian differential categories are categories equipped with a differential combinator which axiomatizes the directional derivative. Important models of Cartesian differential categories include classical differential calculus of smooth functions and categorical models of the differential lambda-calculus. However, Cartesian differential categories cannot account for other interesting notions of differentiation such as the calculus of finite differences or the Boolean differential calculus. On the other hand, change action models have been shown to capture these examples as well as more "exot…
Let $(\mathcal{C},\mathbb{E},\mathfrak{s})$ be an extriangulated category. Given a composition of two commutative squares in $\mathcal{C}$, if two commutative squares are homotopy cartesian, then their composition is also a homotopy cartesian. This covers the result by Mac Lane (1998) for abelian categories and the result by Christensen and Frankland (2022) for triangulated categories.
Using generalized enriched categories, in this paper we show that Rosický's proof of cartesian closedness of the exact completion of the category of topological spaces can be extended to a wide range of topological categories over $\mathsf{Set}$, like metric spaces, approach spaces, ultrametric spaces, probabilistic metric spaces, and bitopological spaces. In order to do so we prove a sufficient criterion for exponentiability of $(\mathbb{T},V)$-categories and show that, under suitable conditions, every $(\mathbb{T},V)$-injective category is exponentiable in $(\mathbb{T},V)\text{-}\mathsf{Cat}…
The Faà di Bruno construction, introduced by Cockett and Seely, constructs a comonad $\mathsf{Fa{\grave{a}}}$ whose coalgebras are precisely Cartesian differential categories. In other words, for a Cartesian left additive category $\mathbb{X}$, $\mathsf{Fa{\grave{a}}}(\mathbb{X})$ is the cofree Cartesian differential category over $\mathbb{X}$. Composition in these cofree Cartesian differential categories is based on the Faà di Bruno formula, and corresponds to composition of differential forms. This composition, however, is somewhat complex and difficult to work with. In this paper we provide…
Regular logic is the fragment of first order logic generated by $=$, $\top$, $\wedge$, and $\exists$. A key feature of this logic is that it is the minimal fragment required to express composition of binary relations; another is that it is the internal logic of regular categories. The link between these two facts is that in any regular category, one may construct a notion of binary relation using jointly-monic spans; this results in what is known as the bicategory of relations of the regular category. In this paper we provide a direct axiomatization of bicategories of relations, which we term …
Cartesian Differential Kleisli Categories
本文引入笛卡尔微分单子，通过从基范畴提升微分组合子使单子的Kleisli范畴成为笛卡尔微分范畴，并利用抽象Kleisli范畴给出精确刻画，证明其Eilenberg-Moore范畴为切范畴。
In this paper, we introduce differential exponential maps in Cartesian differential categories, which generalizes the exponential function $e^x$ from classical differential calculus. A differential exponential map is an endomorphism which is compatible with the differential combinator in such a way that generalizations of $e^0 = 1$, $e^{x+y} = e^x e^y$, and $\frac{\partial e^x}{\partial x} = e^x$ all hold. Every differential exponential map induces a commutative rig, which we call a differential exponential rig, and conversely, every differential exponential rig induces a differential exponent…
Cartesian Linearly Distributive Categories: Revisited
本文重新审视笛卡尔线性分配范畴，证明其强结构性质，并研究了正则分配范畴和半加性范畴等关键例子，同时指出某些之前认为是CLDCs的类别实际上并非如此。
Most often, in a categorical semantics for a programming language, the substitution of terms is expressed by composition and finite products. However this does not deal with the order of evaluation of arguments, which may have major consequences when there are side-effects. In this paper Cartesian effect categories are introduced for solving this issue, and they are compared with strong monads, Freyd-categories and Haskell's Arrows. It is proved that a Cartesian effect category is a Freyd-category where the premonoidal structure is provided by a kind of binary product, called the sequential pr…
It has been proved by Bergh and Thaule that the higher mapping cone axiom is equivalent to the higher octahedral axiom for n-angulated categories. In this note, we use homotopy cartesian diagrams to give several new equivalent statements of the higher mapping cone axiom, which are applied to explain the higher octahedral axiom.
We prove that four different ways of defining Cartesian fibrations and the Cartesian model structure are all Quillen equivalent: On marked simplicial sets, on bisimplicial spaces, on bisimplicial sets, on marked simplicial spaces. The main way to prove these equivalences is by using the Quillen equivalences between quasi-categories and complete Segal spaces as defined by Joyal-Tierney and the straightening construction due to Lurie.
Cartesian double theories: A double-categorical framework for categorical doctrines
本文提出基于双重范畴理论的笛卡尔双重理论框架，统一刻画范畴、幺半范畴等多种范畴结构，并证明其模型构成虚双重范畴或装备，且易于由生成元和关系呈现。
Seely's paper "Locally cartesian closed categories and type theory" contains a well-known result in categorical type theory: that the category of locally cartesian closed categories is equivalent to the category of Martin-Löf type theories with Pi-types, Sigma-types and extensional identity types. However, Seely's proof relies on the problematic assumption that substitution in types can be interpreted by pullbacks. Here we prove a corrected version of Seely's theorem: that the Bénabou-Hofmann interpretation of Martin-Löf type theory in locally cartesian closed categories yields a biequivalence…
From the analogue of Boehm's Theorem proved for the typed lambda calculus, without product types and with them, it is inferred that every cartesian closed category that satisfies an equality between arrows not satisfied in free cartesian closed categories must be a preorder. A new proof is given here of these results, which were obtained previously by Richard Statman and Alex K. Simpson.
We propose a semantics for permutation equivalence in higher-order rewriting. This semantics takes place in cartesian closed 2-categories, and is proved sound and complete.
Cartesian cubical model categories
该研究定义笛卡尔立方集范畴，并利用一元类型理论立方系统构造的思想建立其上的 Quillen 模型结构。
Every category $\mathcal K$ has a free completion $\mathcal P \mathcal K$ under colimits and a free completion $Σ\mathcal K$ under coproducts. A number of properties of $\mathcal K$ transfer to $\mathcal P \mathcal K$ and $Σ\mathcal K$ (e.g., completeness or cartesian closedness). We prove that $\mathcal P\mathcal K$ is always a pretopos, but, for $\mathcal K$ large, seldom a topos. Moreover, for complete categories $\mathcal K$ we prove that $\mathcal P\mathcal K$ is locally cartesian closed whenever $\mathcal K$ is additive or cartesian closed or dual to an extensive category. We also study …
A non-self-contained gathering of notes on category theory, including the definition of locally cartesian closed category, of the cartesian structure in slice categories, or of the pseudo-cartesian structure on Eilenberg-Moore categories. References and proofs are provided, sometimes, to my knowledge, for the first time.
For a relational Horn theory $\mathbb{T}$, we provide useful sufficient conditions for the exponentiability of objects and morphisms in the category $\mathbb{T}\text{-}\mathsf{Mod}$ of $\mathbb{T}$-models; well-known examples of such categories, which have found recent applications in the study of programming language semantics, include the categories of preordered sets and (extended) metric spaces. As a consequence, we obtain useful sufficient conditions for $\mathbb{T}\text{-}\mathsf{Mod}$ to be cartesian closed, locally cartesian closed, and even a quasitopos; in particular, we provide two …
Non-well-founded trees are used in mathematics and computer science, for modelling non-well-founded sets, as well as non-terminating processes or infinite data-structures. Categorically, they arise as final coalgebras for polynomial endofunctors, which we call M-types. In order to reason about trees, we need the notion of path, which can be formalised in the internal logic of any locally cartesian closed pretopos with a natural number object. In such categories, we derive existence results about M-types, leading to stability of locally cartesian closed pretoposes with a natural number object a…
An Ultrametric for Cartesian Differential Categories for Taylor Series Convergence
本文在任意笛卡尔微分范畴中建立了无需极限或无穷和的泰勒级数形式理论，通过泰勒多项式诱导超度量，证明了泰勒范畴中泰勒级数收敛于原映射，统一了微分学与微分λ-演算的展开。
Categories are coreflectively embedded in multicategories via the "discrete cocone" construction, the right adjoint being given by the monoid construction. Furthermore, the adjunction lifts to the "cartesian level": preadditive categories are coreflectively embedded (as theories for many-sorted modules) in cartesian multicategories (general algebraic theories). In particular, one gets a direct link between two ways of considering modules over a rig, namely as additive functors valued in commutative monoids or as models of the theory generated by the rig itself.
We prove that the quasicategories arising from models of Martin-Löf type theory via simplicial localization are locally cartesian closed.
The notion of cartesian bicategory, introduced by Carboni and Walters for locally ordered bicategories, is extended to general bicategories. It is shown that a cartesian bicategory is a symmetric monoidal bicategory.
We show, using Eckmann-Hilton argument, that the category of 3-computads is not cartesian closed. As a corollary we get that neither the category of all computads nor the category of n-computads, for n>2, do form locally cartesian closed categories, and hence elementary toposes.
Cartesian closed and stable subconstructs of [0,1]-Cat
该研究针对单位区间上连续三角模下的实富集范畴，给出其笛卡尔闭稳定子构造的等价刻画，并证明取值于幂等元集的Yoneda完备实富集范畴与Yoneda连续[0,1]-函子构成笛卡尔闭范畴。
Symmetric 2-rigs: coexponentiability and cartesian closure
在对称 2-环的余笛卡尔 2- 范畴 RIG 中研究余可指数性，将余可指数的对称 2-环刻画为小范畴上预层范畴的形变收缩，并以此阐述了 RIG 对偶的两个全子 2- 范畴的笛卡尔闭包。
Locally cartesian closed (lcc) categories are natural categorical models of extensional dependent type theory. This paper introduces the "gros" semantics in the category of lcc categories: Instead of constructing an interpretation in a given individual lcc category, we show that also the category of all lcc categories can be endowed with the structure of a model of dependent type theory. The original interpretation in an individual lcc category can then be recovered by slicing. As in the original interpretation, we face the issue of coherence: Categorical structure is usually preserved by func…
We propose a notion of weak (n+k,n)-category, which we call (n+k,n)-Theta-spaces. The (n+k,n)-Theta-spaces are precisely the fibrant objects of a certain model category structure on the category of presheaves of simplicial sets on Joyal's category Theta_n. This notion is a generalization of that of complete Segal spaces (which are precisely the (infty,1)-Theta-spaces). Our main result is that the above model category is cartesian.
Products in double categories, revisited
本文从无偏视角重新审视双范畴积，提出自由积完成的双范畴类比，扩展了双范畴的表达能力，同时保持单一普遍性质，并通过双重性发展积与余积理论及有限积双理论应用。
Internal languages of locally cartesian closed $(\infty,1)$-categories
本文证明局部笛卡尔闭$(\infty,1)$-范畴的内部语言为马丁-洛夫类型论，包含依赖求和、内涵相等类型和依赖积。
From Gs-monoidal to Oplax Cartesian Categories: Constructions and Functorial Completeness
本文扩展 gs-monoidal 范畴为带箭头预序的 oplax cartesian 范畴，刻画其 Kleisli 与 span 构造，并证明 Yoneda 嵌入及函子完备性定理。
We construct $W$-types in the category of coalgebras for a cartesian comonad. It generalizes the constructions of $W$-types in presheaf toposes and gluing toposes.
After developing the basic theory of locally cartesian localizations of presentable locally cartesian closed infinity-categories, we establish the representability of equivalences and show that univalent families, in the sense of Voevodsky, form a poset isomorphic to the poset of bounded local classes, in the sense of Lurie. It follows that every infinity-topos has a hierarchy of "universal" univalent families, indexed by regular cardinals, and that n-topoi have univalent families classifying (n-2)-truncated maps. We show that univalent families are preserved (and detected) by right adjoints t…
When is Cat(Q) cartesian closed?
本文研究了哪些量词oids Q 使得Cat(Q)为笛卡儿闭合，并统一了已知结果并提供了新例子。
The present paper gives a generalization of cartesian closed categories, called cartesian closed categories with dependence, whose strict version induces categories with families that support 1-, Sigma- and Pi-types in the strict sense. Consequently, we have obtained a new semantics of dependent type theories that is both categorical and true-to-syntax.
We show that the conditions in Steimle's 'additivity theorem for cobordism categories' can be weakened to only require \emph{locally} (co)Cartesian fibrations, making it applicable to a larger class of functors. As an application we compute the difference in classifying spaces between the infinity category of cospans of finite sets and its homotopy category.
Differential lambda-categories were introduced by Bucciarelli et al. as models for the simply typed version of the differential lambda-calculus of Ehrhard and Regnier. A differential lambda-category is a cartesian closed differential category of Blute et al. in which the differential operator is compatible with the closed structure. We prove that any differential lambda-category is equipped with a canonical strong commutative monad whose construction resembles that of the tangent bundle in the category of smooth manifolds. Most of the results of this note remain valid in an arbitrary cartesian…
We introduce the new concept of cartesian module over a pseudofunctor $R$ from a small category to the category of small preadditive categories. Already the case when $R$ is a (strict) functor taking values in the category of commutative rings is sufficient to cover the classical construction of quasi-coherent sheaves of modules over a scheme. On the other hand, our general setting allows for a good theory of contravariant additive locally flat functors, providing a geometrically meaningful extension of Crawley-Boevey's Representation Theorem. As an application, we relate and extend some previ…
I show that any locally Cartesian left localisation of a presentable infinity-category admits a right proper model structure in which all morphisms are cofibrations, and obtain a Koszul duality classification of its fibrations. By a simple criterion in terms of generators for a localisation to be locally Cartesian, this applies to any nullification functor. In particular, it includes examples with non-trivial "homotopical content." I further describe, and provide examples from, the set of fibrations in three contexts: the higher categorical Thomason model structure of Mazel-Gee, where fibratio…
Cartesian Fibrations of $(\infty,2)$-categories
本文在缩放单纯集框架下引入$\infty$-双范畴的四种笛卡尔2-纤维化变体，刻画其提升性质与相容条件，证明等价性可逐纤维检验，并建立富集$\infty$-范畴情形与缩放神经之间的对应关系。
We define and study the notion of a locally bounded enriched category over a (locally bounded) symmetric monoidal closed category, generalizing the locally bounded ordinary categories of Freyd and Kelly. In addition to proving several general results for constructing examples of locally bounded enriched categories and locally bounded closed categories, we demonstrate that locally bounded enriched categories admit fully enriched analogues of many of the convenient results enjoyed by locally bounded ordinary categories. In particular, we prove full enrichments of Freyd and Kelly's reflectivity a…
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。