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We study the relation of two frameworks for multiplicative homotopy theories: Presentably symmetric monoidal $\infty$-categories and combinatorial symmetric monoidal model categories. Our main theorem establishes an equivalence of their…

Category Theory · Mathematics 2026-03-30 Kensuke Arakawa

We investigate conditions for when the $t$-structure of Happel-Reiten-Smal{\o} associated to a torsion pair is a compactly generated $t$-structure. The concept of a $t$CG torsion pair is introduced and for any ring $R$, we prove that…

Category Theory · Mathematics 2018-08-13 Daniel Bravo , Carlos E. Parra

Let $\mathcal{A}$ be a Frobenius category and $\omega$ the full subcategory consisting of projective objects. The relations between special precovering (resp., precovering) ideals in $\mathcal{A}$ and special precovering (resp.,…

Category Theory · Mathematics 2025-02-18 Dandan Sun , Zhongsheng Tan , Qikai Wang , Haiyan Zhu

We abstract and generalize homotopical monadicity statements, placing in a single conceptual framework a range of old and recent recognition and characterization principles in iterated loop space theory in classical, equivariant, and…

Algebraic Topology · Mathematics 2024-02-07 Hana Jia Kong , J. Peter May , Foling Zou

We compute the Mordell-Weil groups of the modular Jacobian varieties of hyperelliptic modular curves $X_1(M, MN)$ over every number field which is the composition of quadratic fields. Also we prove criteria for the existence of elliptic…

Number Theory · Mathematics 2021-11-17 Koji Matsuda

Throughout $A$ will denote commutative noetherian ring, with $\dim A=d\geq 2$, and $P$ denote a projective $A$-module with $rank(P)=n$. In \cite{MM1} we considered the Homotopy obstruction sets $\pi_0\left({\mathcal LO}(P)\right)$, which…

Commutative Algebra · Mathematics 2018-11-13 Satya Mandal , Bibekananda Mishra

We study the classes of modules which are generated by a silting module. In the case of either hereditary or perfect rings it is proved that these are exactly the torsion $\mathcal{T}$ such that the regular module has a special…

Representation Theory · Mathematics 2017-04-06 Simion Breaz , Jan Žemlička

We study extension spaces, cotorsion pairs and their mutations in the cluster category of a marked surface without punctures. Under the one-to-one correspondence between the curves, valued closed curves in the marked surface and the…

Representation Theory · Mathematics 2012-05-09 Jie Zhang , Yu Zhou , Bin Zhu

We prove general results about completeness of cotorsion theories and existence of covers and envelopes in locally presentable abelian categories, extending the well-established theory for module categories and Grothendieck categories.…

Category Theory · Mathematics 2017-04-24 Leonid Positselski , Jiri Rosicky

By the Telescope Conjecture for Module Categories, we mean the following claim: "Let R be any ring and (A, B) be a hereditary cotorsion pair in Mod-R with A and B closed under direct limits. Then (A, B) is of finite type." We prove a…

Rings and Algebras · Mathematics 2008-09-16 Jan Saroch , Jan Stovicek

A commutative ring is said to have ITI with respect to an ideal a if the a-torsion functor preserves injectivity of modules. Classes of rings with ITI or without ITI with respect to certain sets of ideals are identified. Behaviour of ITI…

Commutative Algebra · Mathematics 2016-10-13 Pham Hung Quy , Fred Rohrer

Atiyah and Hirzebruch gave examples ofeven degree torsion classes in the singularcohomology of a smooth complex projective manifold, which arenot Poincar\'{e} dual to an algebraiccycle. We notice that the order ofthese classes are small…

Algebraic Geometry · Mathematics 2007-05-23 C. Soule , C. Voisin

Given a complete hereditary cotorsion pair $(\mathcal{A},\mathcal{B})$ in a Grothendieck category $\mathcal{G}$, the derived category $\mathcal{D}(\mathcal{B})$ of the exact category $\mathcal{B}$ is defined as the quotient of the category…

Category Theory · Mathematics 2019-12-30 Silvana Bazzoni , Marco Tarantino

Homotopy Type Theory is a new field of mathematics based on the surprising and elegant correspondence between Martin-Lofs constructive type theory and abstract homotopy theory. We have a powerful interplay between these disciplines - we can…

Logic in Computer Science · Computer Science 2014-02-10 Kristina Sojakova

We prove that in most cases relevant to cryptography, the Frobenius endomorphism on the Jacobian of a genus two curve is represented by a diagonal matrix with respect to an appropriate basis of the subgroup of l-torsion points. From this…

Algebraic Geometry · Mathematics 2008-02-18 Christian Robenhagen Ravnshoj

The multiplihedra {M_n} form a family of polytopes originating in the study of higher categories and homotopy theory. While the multiplihedra may be unfamiliar to the algebraic combinatorics community, it is nestled between two families of…

Combinatorics · Mathematics 2009-08-27 Stefan Forcey , Aaron Lauve , Frank Sottile

There are two main approaches to the problem of realizing a $\Pi$-algebra (a graded group $\Lambda$ equipped with an action of the primary homotopy operations) as the homotopy groups of a space $X$. Both involve trying to realize an…

Algebraic Topology · Mathematics 2011-07-22 David Blanc , Mark W. Johnson , James M. Turner

Let $\Lambda$ be a left and right noetherian ring. First, for $m,n\in\mathbb{N}\cup\{\infty\}$, we give equivalent conditions for a given $\Lambda$-module to be $n$-torsionfree and have $m$-torsionfree transpose. Using them, we investigate…

Commutative Algebra · Mathematics 2020-10-22 Tokuji Araya , Ryo Takahashi

We give a practical method to compute the 2-torsion subgroup of the Jacobian of a non-hyperelliptic curve of genus $3$, $4$ or $5$. The method is based on the correspondence between the 2-torsion subgroup and the theta hyperplanes to the…

Number Theory · Mathematics 2025-10-22 Elvira Lupoian

Let $R$ be a general ring. Duality pairs of $R$-modules were introduced by Holm-Jorgensen. Most examples satisfy further properties making them what we call semi-complete duality pairs in this paper. We attach a relative theory of…

K-Theory and Homology · Mathematics 2021-05-11 James Gillespie , Alina Iacob