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Related papers: Coformality around fibrations and cofibrations

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In this paper, we introduce a new notion of algebra over a linear $\infty$-operad and a corresponding notion of coalgebra over an $\infty$-cooperad. We next extend the Koszul duality between linear $\infty$-operads and linear…

Category Theory · Mathematics 2026-02-10 Eric Hoffbeck , Ieke Moerdijk

Let G be a topological group such that its homology H(G) with coefficients in a principal ideal domain R is an exterior algebra, generated in odd degrees. We show that the singular cochain functor carries the duality between G-spaces and…

Algebraic Topology · Mathematics 2007-08-13 Matthias Franz

In this paper we continue the study (initiated in a previous article) of linear Koszul duality, a geometric version of the standard duality between modules over symmetric and exterior algebras. We construct this duality in a very general…

Representation Theory · Mathematics 2017-05-17 Ivan Mirković , Simon Riche

We give a criterion for the section ring of an ample line bundle to be Koszul in terms of multigraded regularity. We discuss an application to polytopal semigroup rings.

Algebraic Geometry · Mathematics 2007-12-17 Milena Hering

We address the question of existence of sections of fibrations in two settings. First, we show that a bundle with base a finite 2-complex admits a section if and only if the inclusion of the fiber is $\pi_1$-injective and the associated…

Geometric Topology · Mathematics 2026-04-14 Jonathan A. Hillman , Riccardo Pedrotti

We study an analogue of fibrations of topological spaces with the homotopy lifting property in the setting of C*-algebra bundles. We then derive an analogue of the Leray-Serre spectral sequence to compute the K-theory of the fibration in…

K-Theory and Homology · Mathematics 2008-10-02 Siegfried Echterhoff , Ryszard Nest , Herve Oyono-Oyono

Let (M,F) be a foliated manifold. We study the relationship between the basic cohomology Hb(M,F) of the foliation and the De Rham cohomology H(DF) of the space of leaves M/F as a quotient diffeological space. We prove that for an arbitrary…

Differential Geometry · Mathematics 2007-06-18 E. Macias-Virgos , E. Sanmartin-Carbon

We construct a canonical formulation of general relativity for the case of a timelike foliation of spacetime. The formulation possesses explicit covariance with respect to Lorentz transformations in the tangent space. Applying the loop…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Sergei Alexandrov , Zoltan Kadar

In this note we show that in the simplicial setting, the classifying space construction converts short exact sequences of groups not just to homotopy fibrations, but in fact to fibre bundles.

Algebraic Topology · Mathematics 2025-07-04 Matthias Franz

We define topological invariants of regular Lagrangian fibrations using the integral affine structure on the base space and we show that these coincide with the classes known in the literature. We also classify all symplectic types of…

Symplectic Geometry · Mathematics 2015-05-14 D. Sepe

In this paper, we investigate the moduli of surfaces of general type admitting genus 2 fibrations with irregularity q = g_b + 1, where g_b >= 2 is the genus of the base. We prove that smooth fibrations are parametrized by a unique component…

Algebraic Geometry · Mathematics 2007-05-23 Hursit Onsiper

This paper contains two results on Hodge loci in the moduli space of curves. The first concerns fibrations over curves with a non-trivial flat part in the Fujita decomposition. If local Torelli theorem holds for the fibres and the fibration…

Algebraic Geometry · Mathematics 2020-07-15 Paola Frediani , Alessandro Ghigi , Gian Pietro Pirola

Let k be a commutative ring in which 2 is invertible. We prove that the Hermitian K-theory of quadric hypersurfaces over k admits fibration sequences relating it to the base ring and to Clifford algebras equipped with various duality…

K-Theory and Homology · Mathematics 2026-01-27 Heng Xie

Many examples of obstruction theory can be formulated as the study of when a lift exists in a commutative square. Typically, one of the maps is a cofibration of some sort and the opposite map is a fibration, and there is a functorial…

Algebraic Topology · Mathematics 2017-07-11 J. Daniel Christensen , William G. Dwyer , Daniel C. Isaksen

We study the differential graded Lie algebra of endomorphisms of the Koszul resolution of a regular sequence on a unitary commutative $K$-algebra $R$ and we prove that it is homotopy abelian over $K$, while it is generally not formal over…

Algebraic Geometry · Mathematics 2021-05-25 Francesca Carocci , Marco Manetti

In this paper some results on the topology of the space of $k$-flats in $\mathbb R^n$ are proved, similar to the Borsuk-Ulam theorem on coverings of sphere. Some corollaries on common transversals for families of compact sets in $\mathbb…

Combinatorics · Mathematics 2011-07-06 R. N. Karasev

In 2002, Biss investigated on a kind of fibration which is called rigid covering fibration (we rename it by rigid fibration) with properties similar to covering spaces. In this paper, we obtain a relation between arbitrary topological…

Algebraic Topology · Mathematics 2017-11-28 Tayyebe Nasri , Behrooz Mashayekhy

We extend the notion of topological T-duality from oriented sphere bundles to transgressive fibrations, a more general type fibration characterised by the abundance of transgressive elements. Examples of transgressive fibrations include…

Differential Geometry · Mathematics 2025-08-05 Gil R. Cavalcanti

A hyperplane arrangement is called formal provided all linear dependencies among the defining forms of the hyperplanes are generated by ones corresponding to intersections of codimension two. The significance of this notion stems from the…

Combinatorics · Mathematics 2024-07-03 Tilman Möller , Paul Mücksch , Gerhard Roehrle

Let $A \Rightarrow M$ be a Lie algebroid. In this short note, we prove that a pull-back of $A$ along a fibration with homologically $k$-connected fibers, shares the same deformation cohomology of $A$ up to degree $k$.

Differential Geometry · Mathematics 2018-04-20 Giovanni Sparano , Luca Vitagliano