Results 51 to 60 of about 1,003,210 (193)
A cohomological characterisation of Yu's Property A for metric spaces
, 2012 We introduce the notion of an asymptotically invariant mean as a coarse averaging operator for a metric space and show that the existence of such an operator is equivalent to Yu’s property A.
Wright, Nick +2 more
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Dimension-raising theorems for cohomological and extension dimensions [PDF]
, 2008 We establish cohomological and extension dimension versions of the Hurewicz dimension-raising ...
Vesko Valov +3 more
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K-Orbit closures and Hessenberg varieties
Forum of Mathematics, SigmaThis article explores the relationship between Hessenberg varieties associated with semisimple operators with two eigenvalues and orbit closures of a spherical subgroup of the general linear group.
Mahir Bilen Can +3 more
doaj +1 more source
Low eigenvalues of the p$p$–Laplacian in general open sets
Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.Abstract We consider the minmax Ljusternik–Schnirelmann levels of the constrained p$p$–Dirichlet integral on a general open set of the Euclidean space. We show that, whenever one of these levels lies below the threshold given by the Lp$L^p$ Poincaré constant “at infinity,” it actually defines an eigenvalue of the Dirichlet p$p$–Laplacian. We also prove
Lorenzo Brasco +2 more
wiley +1 more source
Homological dimension and Farrell cohomology
Journal of Algebra, 1984 \textit{F. T. Farrell} [J. Pure Appl. Algebra 10, 153--161 (1978; Zbl 0373.20050)] constructed a cohomology theory for groups of finite virtual cohomological dimension which generalizes the Tate cohomology theory of finite groups. In this very interesting paper the author extends Farrell cohomology to a class of groups larger than the class of groups ...
openaire +2 more sources
An EZ${\mathcal {E}\mathcal {Z}}$‐structure for the mapping class group
Proceedings of the London Mathematical Society, Volume 133, Issue 2, August 2026.Abstract We construct a boundary for the mapping class group Mod(S)${\rm Mod}(S)$ of a surface S$S$ of finite type. The action of Mod(S)${\rm Mod}(S)$ on this boundary is minimal, strongly proximal and topologically free. The boundary is the boundary of an EZ${\mathcal {E}\mathcal {Z}}$‐structure for Mod(S)${\rm Mod}(S)$.
Ursula Hamenstädt
wiley +1 more source
Cohomological and projective dimensions [PDF]
Compositio Mathematica, 2013 Abstract Let $\mathfrak{a}$ be a homogeneous ideal of a polynomial ring
openaire +3 more sources
Determining the cohomological dimension of certain compacta
, 1987 In previous work of this author and of John J. Walsh it was shown that many of the known examples of hereditarily infinite dimensional compacta have infinite cohomological dimension.
Leonard R. Rubin
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Arithmeticity for integral cohomological dimension of configuration spaces of manifolds [PDF]
, 2023 Consider the configuration spaces of manifolds. We give a precise formula for the integral cohomological dimension (the degree of top non-trivial integral cohomology group) of unordered configuration spaces of manifolds with non-trivial co-dimension one ...
Yameen, Muhammad
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Recognising flag varieties and reductive groups
Proceedings of the London Mathematical Society, Volume 133, Issue 2, August 2026.Abstract Fix a flat and projective morphism X→Σ$X\rightarrow \Sigma$ of schemes. We show, first, that any set of P1${\mathbb {P}}^1$‐fibrations on X$X$ defines a set of simple roots, a set of simple coroots and a Cartan matrix C$C$. Second, X$X$ is an étale F${\mathcal {F}}$‐bundle over some projective Σ$\Sigma$‐scheme, where F${\mathcal {F}}$ is the ...
Ian Grojnowski +1 more
wiley +1 more source