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Related papers: B\'enabou's theorem for pseudoadjunctions

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The Jump Inversion Theorem says that for every real $A \ge_T 0'$ there is a real $B$ such that $A \equiv_T B' \equiv_T B \oplus 0'$. A known refinement of this theorem says that we can choose $B$ to be a member of any special $\Pi^0_1$…

Logic · Mathematics 2021-02-12 Hayden R. Jananthan , Stephen G. Simpson

We give an unconditional proof of the Coba conjecture for wonderful compactifications of adjoint type for semisimple Lie groups of type $A_n$. We also give a proof of a slightly weaker conjecture for wonderful compactifications of adjoint…

Algebraic Geometry · Mathematics 2025-04-08 Christopher Manon , David McKinnon , Matthew Satriano

We introduce the notion of Kan injectivity in 2-categories and study its properties. For an adequate 2-category $\mathcal{K}$, we show that every set of morphisms $\mathcal{H}$ induces a KZ-pseudomonad on $\mathcal{K}$ whose 2-category of…

Category Theory · Mathematics 2025-10-16 Ivan Di Liberti , Gabriele Lobbia , Lurdes Sousa

We investigate the conditions that are sufficient to make the Ext-algebra of an object in a (triangulated) category into a Frobenius algebra and compute the corresponding Nakayama automorphism. As an application, we prove the conjecture…

Rings and Algebras · Mathematics 2016-10-18 Manuel Reyes , Daniel Rogalski , James J. Zhang

We generalise to a group homomorphism $\tau$ the $\chi$-graded categories of S\"{o}zer and Virelizier. These are categories in which both morphisms and objects have compatible degrees. We give a 'half-enriched' Yoneda lemma, a structure…

Category Theory · Mathematics 2026-02-06 Jonathan Davies

G. Conner and K. Eda (Topology and its Applications, 146, (2005), 317-328.) introduced a new construction of spaces from groups. They remarked that the construction is not categorical. In this paper, based on the work of Conner and Eda, we…

Algebraic Topology · Mathematics 2011-03-10 Hanieh Mirebrahimi , Behrooz Mashayekhy

We contribute to the formal theory of pseudomonads, i.e. the analogue for pseudomonads of the formal theory of monads. In particular, we solve a problem posed by Steve Lack by proving that, for every Gray-category K, there is a…

Category Theory · Mathematics 2021-01-21 Nicola Gambino , Gabriele Lobbia

We give a complete proof of the B\'enabou-Roubaud monadic descent theorem using the graphical calculus of string diagrams. Our proof links the monadic and Grothendieck's original viewpoint on descent via an internal-category-based…

Category Theory · Mathematics 2026-01-13 Jovana Obradović

The subject of this paper is the higher structure of the strictification adjunction, which relates the two fundamental bases of three-dimensional category theory: the $\mathbf{Gray}$-category of $2$-categories and the tricategory of…

Category Theory · Mathematics 2019-02-06 Alexander Campbell

Let $A$ be a unital separable simple infinite dimensional \CA with tracial rank no more than one and with the tracial state space $T(A)$ and let $U(A)$ be the unitary group of $A.$ Suppose that $u\in U_0(A),$ the connected component of…

Operator Algebras · Mathematics 2009-02-03 Huaxin Lin

Let $\mathcal{A}$ be an abelian category and let $F$ be a subbifunctor of the additive bifunctor $\text{Ext}_{\mathcal{A}}^{1}(-,-)\colon \mathcal{A}^{\text{op}}\times \mathcal{A}\to \mathsf{Ab}$. Buan proved in [4] that $F$ is closed if,…

Category Theory · Mathematics 2025-06-03 Juan Camilo Cala

We prove that there is a monadic adjunction between the category of bounded posets and the category of pseudo effect algebras.

Rings and Algebras · Mathematics 2022-10-03 Gejza Jenča

The homotopy theory of higher categorical structures has become a relevant part of the machinery of algebraic topology and algebraic K-theory, and this paper contains contributions to the study of the relationship between B\'enabou's…

Category Theory · Mathematics 2014-04-11 A. M. Cegarra , B. A. Heredia , J. Remedios

We develop a bicategorical setup in which one can speak about adjoint 1-morphisms even in the absence of genuine identity 1-morphisms. We also investigate which part of 2-representation theory of 2-categories extends to this new setup.

Category Theory · Mathematics 2020-03-11 Hankyung Ko , Volodymyr Mazorchuk , Xiaoting Zhang

Let P be a semigroup that admits an embedding into a group G. Assume that the embedding satisfies a certain Toeplitz condition and that the Baum-Connes conjecture holds for G. We prove a formula describing the K- theory of the reduced…

Operator Algebras · Mathematics 2012-05-25 Joachim Cuntz , Siegfried Echterhoff , Xin Li

As an example of the categorical apparatus of pseudo algebras over 2-theories, we show that pseudo algebras over the 2-theory of categories can be viewed as pseudo double categories with folding or as appropriate 2-functors into…

Category Theory · Mathematics 2011-11-09 Thomas M. Fiore

There are two main constructions in classical descent theory: the category of algebras and the descent category, which are known to be examples of weighted bilimits. We give a formal approach to descent theory, employing formal consequences…

Category Theory · Mathematics 2019-02-05 Fernando Lucatelli Nunes

In this addendum to [4], we provide a pair of counterexamples relevant to the theory of implicit operations. More precisely, we exhibit a pp expansion of a variety that fails to be a variety (although it is a quasivariety). Furthermore, we…

Rings and Algebras · Mathematics 2026-01-05 Luca Carai , Miriam Kurtzhals , Tommaso Moraschini

In this monograph we provide an in-depth and systematic study of pseudolimits of pseudofunctors $F:\mathscr{C}^{op} \to \mathfrak{Cat}$ in the $2$-category of categories where $\mathscr{C}$ is a $1$-category and use this to give an explicit…

Algebraic Geometry · Mathematics 2024-01-19 Geoff Vooys

For any 0-cell $B$ in a 2-category $\Bc$ we introduce the notion of adjoint algebra $\adj_B$. This is an algebra in the center of $\Bc$. We prove that, if $\ca$ is a finite tensor category, this notion applied to the 2-category of…

Quantum Algebra · Mathematics 2021-03-23 Noelia Bortolussi , Martín Mombelli