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

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We compute the cohomology of the subalgebra $A^{C_2}(1)$ of the $C_2$-equivariant Steenrod algebra $A^{C_2}$. This serves as the input to the $C_2$-equivariant Adams spectral sequence converging to the $RO(C_2)$-graded homotopy groups of an…

Algebraic Topology · Mathematics 2019-10-16 Bertrand J. Guillou , Michael A. Hill , Daniel C. Isaksen , Douglas C. Ravenel

In this paper, we compute the $RO(C_n)$-graded coefficient ring of equivariant cohomology for cyclic groups $C_n$, in the case of Burnside ring coefficients, and in the case of constant coefficients. We use the invertible Mackey functors…

Algebraic Topology · Mathematics 2024-03-04 Samik Basu , Pinka Dey

In this short note, we compute the rational $C_{2^n}$-equivariant stable stems and give minimal presentations for the $RO(C_{2^n})$-graded Bredon cohomology of the equivariant classifying spaces $B_{C_{2^n}}S^1$ and $B_{C_{2^n}}\Sigma_2$…

Algebraic Topology · Mathematics 2021-04-27 Nick Georgakopoulos

We compute the Borel equivariant cohomology ring of the left $K$-action on a homogeneous space $G/H$, where $G$ is a connected Lie group, $H$ and $K$ are closed, connected subgroups and $2$ and the torsion primes of the Lie groups are units…

Algebraic Topology · Mathematics 2025-12-24 Jeffrey D. Carlson

We show by studying the symplectic geometry of the extended moduli space that the intersection cohomology of the representation space $Hom(\pi_1(\Sigma),G)/G$ for a simply connected compact Lie group $G$ is naturally embedded into the $G$…

Algebraic Geometry · Mathematics 2007-05-23 Young-Hoon Kiem

We find a remarkable family of $\mathrm{G}_2$ structures defined on certain principal $\mathrm{SO}(3)$-bundles $P_\pm\longrightarrow M$ associated with any given oriented Riemannian 4-manifold $M$. Such structures are always cocalibrated.…

Differential Geometry · Mathematics 2020-03-27 Rui Albuquerque

With $G = \mathbb{Z}/p$, $p$ prime, we calculate the ordinary $G$-cohomology (with Burnside ring coefficients) of $\mathbb{C}P_G^\infty = B_G U(1)$, the complex projective space, a model for the classifying space for $G$-equivariant complex…

Algebraic Topology · Mathematics 2017-08-22 Steven R. Costenoble

We prove a formula for the structure constants of multiplication of equivariant Schubert classes in both equivariant cohomology and equivariant K-theory of Kac-Moody flag manifolds G/B. We introduce new operators whose coefficients compute…

Algebraic Geometry · Mathematics 2021-09-16 Rebecca Goldin , Allen Knutson

For each of the groups $G = O(2), SU(2), U(2)$, we compute the integral and $\mathbb{F}_2$-cohomology rings of $B_\text{com} G$ (the classifying space for commutativity of $G$), the action of the Steenrod algebra on the mod 2 cohomology,…

Algebraic Topology · Mathematics 2019-07-17 Omar Antolín-Camarena , Simon Gritschacher , Bernardo Villarreal

We describe the connected components of the space $\text{Hom}(\Gamma,SU(2))$ of homomorphisms for a discrete nilpotent group $\Gamma$. The connected components arising from homomorphisms with non-abelian image turn out to be homeomorphic to…

Algebraic Topology · Mathematics 2021-10-22 Omar Antolín Camarena , Bernardo Villarreal

The main objective of this paper is to compute $RO(G)$-graded cohomology of $G$-orbits for the group $G=C_n$, where $n$ is a product of distinct primes. We compute these groups for the constant Mackey functor $\underline{Z}$ and for the…

Algebraic Topology · Mathematics 2024-04-24 Samik Basu , Surojit Ghosh

Over the real numbers with $\Z/2-$coefficients, we compute the $C_2$-equivariant Borel motivic cohomology ring, the Bredon motivic cohomology groups and prove that the Bredon motivic cohomology ring of the real numbers is a proper subring…

Algebraic Geometry · Mathematics 2025-05-28 Bill Deng , Mircea Voineagu

In this, the second of three papers about $C_2$-equivariant complex quadrics, we calculate the equivariant ordinary cohomology of smooth symmetric quadrics graded on the representation ring of $\Pi BU(1)$ and with coefficients in the…

Algebraic Topology · Mathematics 2025-11-19 Steven R. Costenoble , Thomas Hudson

Over the complex numbers, we compute the $C_2$-equivariant Bredon motivic cohomology ring with $\mathbb{Z}/2$ coefficients. By rigidity, this extends Suslin's calculation of the motivic cohomology ring of algebraically closed fields of…

Algebraic Geometry · Mathematics 2023-11-01 Jeremiah Heller , Mircea Voineagu , Paul Arne Østvær

We find a dual version of a previous double-bosonisation theorem whereby each finite-dimensional braided-Hopf algebra $B$ in the category of comodules of a coquasitriangular Hopf algebra $A$ has an associated coquasitriangular Hopf algebra…

Quantum Algebra · Mathematics 2018-06-25 Ryan Kasyfil Aziz , Shahn Majid

We prove that the ideal in complex cobordism ring $\MU^*$ generated by the polynomial generators $S=(x_1, x_k, k\geq 3)$ of $c_1$-spherical cobordism ring $W^*$, viewed as elements in $\MU^*$ by forgetful map is prime. Using the…

Algebraic Topology · Mathematics 2023-10-31 Malkhaz Bakuradze

Starting from a 6-dimensional nilpotent Lie group N endowed with an invariant SU(3) structure, we construct a homogeneous conformally parallel G_2-metric on an associated solvmanifold. We classify all half-flat SU(3) structures that endow…

Differential Geometry · Mathematics 2012-06-19 Simon G. Chiossi , Anna Fino

Let $\mathbf{B}PU_{n}$ be the classifying space of $PU_n$, the projective unitary group of order $n$, for $n>1$. We use the Serre spectral sequence associated to a fiber sequence $\mathbf{B}U_n\rightarrow\mathbf{B}PU_n\rightarrow…

Algebraic Topology · Mathematics 2019-09-17 Xing Gu

This article investigates equivariant parametrized cellular cohomology, a cohomology theory introduced by Costenoble-Waner for spaces with an action by a compact Lie group $G$. The theory extends the $RO(G)$-graded cohomology of a $G$-space…

Algebraic Topology · Mathematics 2024-10-21 Agnès Beaudry , Chloe Lewis , Clover May , Sabrina Pauli , Elizabeth Tatum

Motivic cohomology is powerful tool in algebraic geometry with associated realization maps giving important information about the relations between cohomological invariants of schemes and their classifying spaces. The problem of computing…

Algebraic Geometry · Mathematics 2024-12-19 Alexander Port