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In recent years, spectral clustering has become a standard method for data analysis used in a broad range of applications. In this paper we propose a new class of algorithms for multiway spectral clustering based on optimization of a…

Machine Learning · Computer Science 2016-05-05 James Voss , Mikhail Belkin , Luis Rademacher

Let $\mathcal{A}$ and $\mathcal{B}$ be abelian categories and $\mathbf{F}:\mathcal{A}\to \mathcal{B}$ an additive and right exact functor which is perfect, and let $(\mathbf{F},\mathcal{B})$ be the left comma category. We give an equivalent…

Rings and Algebras · Mathematics 2019-11-13 Yeyang Peng , Rongmin Zhu , Zhaoyong Huang

In this paper we adapt previous work on rewriting string diagrams using hypergraphs to the case where the underlying category has a traced comonoid structure, in which wires can be forked and the outputs of a morphism can be connected to…

Logic in Computer Science · Computer Science 2026-01-14 Dan R. Ghica , George Kaye

The main result of this paper is that there is sometimes a triangulated equivalence between $D_Q( A )$, the $Q$-shaped derived category of an algebra $A$, and $D( B )$, the classic derived category of a different algebra $B$. By…

Representation Theory · Mathematics 2025-01-22 Sira Gratz , Henrik Holm , Peter Jorgensen , Greg Stevenson

In this paper, we provide an interpretation of the existing reduction process for extriangulated categories in general. This process allows us to obtain a new category which, for well-known cases, admits a triangulated structure. We will…

Representation Theory · Mathematics 2025-07-08 Mindy Y. Huerta

We introduce multi-centered dilatations of rings, schemes and algebraic spaces, a basic algebraic concept. Dilatations of schemes endowed with a structure (e.g. monoid, group or Lie algebra) are in favorable cases schemes endowed with the…

Algebraic Geometry · Mathematics 2024-11-05 Arnaud Mayeux

In this paper, we study ideal approximation theory associated to almost $n$-exact structures in extension closed subcategories of $n$-angulated categories. For $n=3$, an $n$-angulated category is nothing but a classical triangulated…

Rings and Algebras · Mathematics 2020-12-08 Lingling Tan , Dingguo Wang , Tiwei Zhao

Every Serre subcategory of an abelian category is assigned a unique type. The type of a Serre subcategory of a Grothendieck category is in the list: $$(0, 0), \ (0, -1), \ (1, -1), \ (0, -2), \ (1, -2), \ (2, -1), \ (+\infty, -\infty);$$…

Category Theory · Mathematics 2017-05-10 Jian Feng , Pu Zhang

Given a category, one may construct slices of it. That is, one builds a new category whose objects are the morphisms from the category with a fixed codomain and morphisms certain commutative triangles. If the category is a groupoid, so that…

Category Theory · Mathematics 2021-08-16 Nicholas Cooney , Jan E. Grabowski

Let $T$ be an infinitely generated tilting module of projective dimension at most one over an arbitrary associative ring $A$, and let $B$ be the endomorphism ring of $T$. In this paper, we prove that if $T$ is good then there exists a ring…

Representation Theory · Mathematics 2014-02-26 Hongxing Chen , Changchang Xi

Usually, mathematical objects have highly parallel interpretations. In this paper, we consider them as sequential constructors of other objects. In particular, we prove that every reflexive directed graph can be interpreted as a program…

Combinatorics · Mathematics 2007-10-27 Serge Burckel

We establish a theory of complexes of relative correspondences. The theory generalizes the known theory of complexes of correspondences of smooth projective varieties. It will be applied in the sequel of this paper to the construction of…

Algebraic Geometry · Mathematics 2014-01-03 Masaki Hanamura

We define duality triples and duality pairs in compactly generated triangulated categories and investigate their properties. This enables us to give an elementary way to determine whether a class is closed under pure subobjects, pure…

Category Theory · Mathematics 2024-09-16 Isaac Bird , Jordan Williamson

We consider categories of generalized perverse sheaves, with relaxed constructibility conditions, by means of the process of gluing $t$-structures and we exhibit explicit abelian categories defined in terms of standard sheaves categories…

Algebraic Geometry · Mathematics 2007-05-23 F. Gudiel-Rodriguez , L. Narvaez-Macarro

In this article we describe the triangulated structure of the bounded derived category of a gentle algebra by describing the triangles induced by the morphisms between indecomposable objects in a basis of their Hom-space.

Representation Theory · Mathematics 2020-01-27 Ilke Canakci , David Pauksztello , Sibylle Schroll

We introduce collages of string diagrams as a diagrammatic syntax for glueing multiple monoidal categories. Collages of string diagrams are interpreted as pointed bimodular profunctors. As the main examples of this technique, we introduce…

Category Theory · Mathematics 2023-12-15 Dylan Braithwaite , Mario Román

In these notes, we describe several geometric interpretations of $H^2(X)$ when $X$ is a trisected 4-manifold. The main insight is that, by analogy with Hodge theory and sheaf cohomology in algebraic geometry, classes in $H^2(X)$ can be…

Geometric Topology · Mathematics 2020-09-15 Peter Lambert-Cole

Extriangulated categories were introduced by Nakaoka and Palu as a simultaneous generalization of exact categories and triangulated categories. In this paper, we first introduce the concept of left Frobenius pairs on an extriangulated…

Category Theory · Mathematics 2021-08-31 Yajun Ma , Haiyu Liu , Yuxian Geng

We consider triangulated orbit categories, with the motivating example of cluster categories, in their usual context of algebraic triangulated categories, then present them from another perspective in the framework of topological…

Algebraic Topology · Mathematics 2014-11-14 Julia E. Bergner , Marcy Robertson

Lenses may be characterised as objects in the category of algebras over a monad, however they are often understood instead as morphisms, which propagate updates between systems. Working internally to a category with pullbacks, we define…

Category Theory · Mathematics 2020-09-16 Bryce Clarke