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We introduce the notion of Lipschitz cohomology classes of a group with local coefficients and reduce the Novikov higher signature conjecture for a group $\Gamma$ to the question whether the Berstein-Schwarz class $\beta_\Gamma\in…

Geometric Topology · Mathematics 2023-11-22 Alexander Dranishnikov

In the 90s, based on presentations of 3-manifolds by Heegaard diagrams, Kuperberg associated a scalar invariant of 3-manifolds to each finite dimensional involutory Hopf algebra over a field. We generalize this construction to the case of…

Geometric Topology · Mathematics 2019-10-30 Rinat Kashaev , Alexis Virelizier

Following Radford's proof of Lagrange's theorem for pointed Hopf algebras, we prove Lagrange's theorem for Hopf monoids in the category of connected species. As a corollary, we obtain necessary conditions for a given subspecies K of a Hopf…

Combinatorics · Mathematics 2019-08-15 Marcelo Aguiar , Aaron Lauve

In this paper we prove a tertiary index theorem which relates a spectral geometric and a homotopy theoretic invariant of an almost complex manifold with framed boundary. It is derived from the index theoretic and homotopy theoretic versions…

Algebraic Topology · Mathematics 2009-09-11 Ulrich Bunke , Niko Naumann

It is well-known that numerically approximating calculus of variations problems possessing a Lavrentiev Gap Phenomenon (LGP) is challenging, and the standard numerical methodologies, such as finite element, finite difference, and…

Numerical Analysis · Mathematics 2025-12-01 Xiaobing Feng , Joshua M. Siktar

In this paper we study variations of the Hopf theorem concerning continuous maps $f$ of a compact Riemannian manifold $M$ of dimension $n$ to $\mathbb{R}^n$. We investigate the case when $M$ is a closed convex $n$-dimensional surface and…

Metric Geometry · Mathematics 2025-04-22 I. M. Shirokov

In the present paper we study some homotopy invariants which can be defined by means of bundles with fiber a matrix algebra. We also introduce some generalization of the Brauer group in the topological context and show that any its element…

Algebraic Topology · Mathematics 2007-05-23 A. V. Ershov

The first author's geometric Hopf invariant of a stable map $F:\Sigma^{\infty}X \to \Sigma^{\infty}Y$ is a stable ${\mathbb Z}_2$-equivariant map $h(F):\Sigma^{\infty}X \to \Sigma^{\infty}(Y \wedge Y)$ constructed by an explicit difference…

Algebraic Topology · Mathematics 2017-10-09 Michael Crabb , Andrew Ranicki

The goal of this paper is to set up the general framework of higher-dimensional Heegaard Floer homology, define the contact class, and use it to give an obstruction to the Liouville fillability of a contact manifold and a sufficient…

Symplectic Geometry · Mathematics 2020-06-11 Vincent Colin , Ko Honda , Yin Tian

Although topological band theory has been used to discover and classify a wide array of novel topological phases in insulating and semi-metal systems, it is not well-suited to identifying topological phenomena in metallic or gapless…

Mesoscale and Nanoscale Physics · Physics 2022-09-13 Alexander Cerjan , Terry A. Loring

In this paper we establish some foundations regarding sheaves of vector spaces on graphs and their invariants, such as homology groups and their limits. We then use these ideas to prove the Hanna Neumann Conjecture of the 1950's; in fact,…

Combinatorics · Mathematics 2011-06-20 Joel Friedman

We develop an appropriate dihedral extension of the Connes-Moscovici characteristic map for Hopf *-algebras. We then observe that one can use this extension together with the dihedral Chern character to detect non-trivial $L$-theory classes…

K-Theory and Homology · Mathematics 2020-03-03 A. Kaygun , S. Sütlü

We establish an upper bound for the cochain type level of the total space of a pull-back fibration. It explains to us why the numerical invariant for a principal bundle over the sphere are less than or equal to two. Moreover computational…

Algebraic Topology · Mathematics 2011-02-17 Katsuhiko Kuribayashi

The primary goal of this paper is to study topological invariants in two dimensional twofold rotation and time-reversal symmetric spinful systems. In this paper, firstly we build a new homotopy invariant based on the lifting of the Wilson…

Mesoscale and Nanoscale Physics · Physics 2021-08-02 Haoshu Li , Shaolong Wan

In this article we study the Arnold conjecture in settings where objects under consideration are no longer smooth but only continuous. The example of a Hamiltonian homeomorphism, on any closed symplectic manifold of dimension greater than…

Symplectic Geometry · Mathematics 2020-11-18 Lev Buhovsky , Vincent Humilière , Sobhan Seyfaddini

The Hopf conjecture states that an even-dimensional, positively curved Riemannian manifold has positive Euler characteristic. We prove this conjecture under the additional assumption that a torus acts by isometries and has dimension bounded…

Differential Geometry · Mathematics 2016-01-20 Lee Kennard

In this paper we develop the homological version of $\Sigma$-theory for locally compact Hausdorff groups, leaving the homotopical version for another paper. Both versions are connected by a Hurewicz-like theorem. They can be thought of as…

Algebraic Topology · Mathematics 2025-08-04 Kai-Uwe Bux , Elisa Hartmann , José Pedro Quintanilha

In this article, we develop an $L^{2}$-Hodge theory on complete $2n$-dimensional almost K\"{a}hler manifolds $(X,\omega)$. In the first part, we establish several identities for various Laplacians, generalized Hodge and Serre dualities, a…

Differential Geometry · Mathematics 2026-05-29 Teng Huang , Qiang Tan , Pan Zhang

First we survey and explain the strategy of some recent results that construct holomorphic $\text{sl}(2, \mathbb C)$-differential systems over some Riemann surfaces $\Sigma_g$ of genus $g\geq 2$, satisfying the condition that the image of…

Differential Geometry · Mathematics 2023-10-26 Indranil Biswas , Sorin Dumitrescu , Lynn Heller , Sebastian Heller , João Pedro dos Santos

M. Hennings and G. Kuperberg defined quantum invariants Z_{Henn} and Z_{Kup} of closed oriented 3-manifolds based on certain Hopf algebras, respectively. We prove that |Z_{Kup}|=|Z_{Henn}|^2 for lens spaces when both invariants are based on…

Quantum Algebra · Mathematics 2012-12-17 Liang Chang , Zhenghan Wang