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Related papers: The $\mathrm{RO}(G)$-Graded Cohomology of the Equi…

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Let G=SU(2) and let \Omega G denote the space of continuous based loops in G, equipped with the pointwise conjugation action of G. It is a classical fact in topology that the ordinary cohomology H^*(\Omega G) is a divided polynomial algebra…

K-Theory and Homology · Mathematics 2012-06-11 Megumi Harada , Lisa C. Jeffrey , Paul Selick

This paper studies $B(r)$, the space of $r$-tuples of $2 \times 2$ complex matrices that generate $\operatorname{Mat}_{2 \times 2}(\mathbf C)$ as an algebra, considered up to change-of-basis. We show that $B(2)$ is homotopy equivalent to…

Rings and Algebras · Mathematics 2024-01-04 W. S. Gant , Ben Williams

Let $C_2$ be the cyclic group of order two. We show that the $RO(C_2)$-graded Bredon cohomology of a finite Rep($C_2$)-complex is free as a module over the cohomology of a point when using coefficients in the constant Mackey functor…

Algebraic Topology · Mathematics 2021-09-14 Eric Hogle , Clover May

We study the cohomology of the free loop space of $SU(n+1)/T^n$, the simplest example of a complete flag manifolds and an important homogeneous space. Through this enhanced analysis we reveal rich new combinatorial structures arising in the…

Algebraic Topology · Mathematics 2022-10-25 Matthew I. Burfitt , Jelena Grbić

We study the topology of the moduli space of flat SU(2)-bundles over a nonorientable surface X. This moduli space may be identified with the space of homomorphisms Hom(\pi_1(X),SU(2)) modulo conjugation by SU(2). In particular, we compute…

Symplectic Geometry · Mathematics 2009-02-06 Thomas Baird

We completely calculate the $RO(G)$-graded coefficients of ordinary equivariant cohomology where $G$ is the dihedral group of order $2p$ for a prime $p>2$ both with constant and Burnside ring coefficients. The authors first proved it for…

Algebraic Topology · Mathematics 2020-05-05 Igor Kriz , Yunze Lu

We compute the equivariant homology and cohomology of projective spaces with integer coefficients. More precisely, in the case of cyclic groups, we show that the cellular filtration of the projective space $P(k\rho )$, of lines inside…

Algebraic Topology · Mathematics 2025-09-24 Samik Basu , Pinka Dey , Aparajita Karmakar

Motivated by the fact that ordinary linear duality does not in general produce a coalgebra structure from an infinite-dimensional algebra, we develop a Sweedler-type finite dual construction for BiHom-associative algebras. For a…

Rings and Algebras · Mathematics 2026-01-30 Jiacheng Sun

Bryant and Salamon gave a construction of metrics of G2 holonomy on the total space of the bundle of anti-self-dual (ASD) 2-forms over a 4-dimensional self-dual Einstein manifold. We generalise it by considering the total space of an SO(3)…

High Energy Physics - Theory · Physics 2022-12-06 Yannick Herfray , Kirill Krasnov , Carlos Scarinci , Yuri Shtanov

We consider two different $\text{SU}(2)^2$-invariant cohomogeneity one manifolds, one non-compact $M=\mathbb{R}^4 \times S^3$ and one compact $M=S^4 \times S^3$, and study the existence of coclosed $\text{SU}(2)^2$-invariant…

Differential Geometry · Mathematics 2024-12-06 Izar Alonso

Let $BPU(n)$ be the classifying space of the projective unitary group $PU(n)$. We determine the integral cohomology ring of $BPU(4)$, and the Steenrod algebra structure of its mod $2$ cohomology.

Algebraic Topology · Mathematics 2024-10-16 Feifei Fan

We consider families of reductive complexes related by level-raising operators and originating from an associative algebra. In the main theorem it is shown that the multiple cohomology of that complexes is given by the factor space of…

Functional Analysis · Mathematics 2024-08-13 A. Zuevsky

In this paper, we compute the $RO(C_{pq})$-graded cohomology of $C_{pq}$-orbits. We deduce that in all the cases the Bredon cohomology groups are a function of the fixed point dimensions of the underlying virtual representations. Further,…

Algebraic Topology · Mathematics 2019-02-06 Samik Basu , Surojit Ghosh

In this paper, we compute explicitly both the $K$-theory and integral cohomology rings of the space of commuting elements in $SU(2)$ via the $K$-theory of its desingularization. We also briefly discuss the different behavior of its…

Algebraic Topology · Mathematics 2025-10-20 Chi-Kwong Fok

The spaces BG_2 and BDI(4) have the property that their mod 2 cohomology is given by the rank 3 and 4 Dickson invariants respectively. Associated with these spaces one has for q odd the classifying spaces of the finite groups BG_2(q)and the…

Algebraic Topology · Mathematics 2011-04-01 Ran Levi , Nora Seeliger

We prove new structural results for the rational homotopy type of the classifying space $B\operatorname{aut}(X)$ of fibrations with fiber a simply connected finite CW-complex $X$. We first study nilpotent covers of $B\operatorname{aut}(X)$…

Algebraic Topology · Mathematics 2025-10-15 Alexander Berglund , Tomáš Zeman

In the study of the Type II superstring, it is useful to consider the BRST complex associated to the sum of two pure spinors. The cohomology of this complex is an infinite-dimensional vector space. It is also a finite-dimensional algebra…

High Energy Physics - Theory · Physics 2013-07-22 Andrei Mikhailov , Albert Schwarz , Renjun Xu

We study the $RO(G)$-graded Bredon cohomology of a point in the case where $G$ is a cyclic group of odd order, expanding on the information provided by previous studies. Our methods center on the purely algebraic aspects of this matter,…

Algebraic Topology · Mathematics 2026-02-24 Daniel Dugger , Christy Hazel

We provide an explicit description of the Poincar\'e dual of each generator of the rational cohomology ring of the $SU(2)$ character variety for a genus $g$ surface with central extension -- equivalently, that of the moduli space of stable…

Differential Geometry · Mathematics 2020-12-14 Lisa Jeffrey , Aidan Lindberg , Steven Rayan

The complex Lie group GO(2n,C) by definition consists of all complex matrices A of size 2n, such that A times transpose(A) is a non-zero scalar. In this paper we determine explicitly the singular cohomology ring of the classifying space…

Algebraic Topology · Mathematics 2007-05-23 Yogish I. Holla , Nitin Nitsure