Degree of T-equivariant maps in ℝⁿ

Joanna Janczewska; Marcin Styborski

Displaying similar documents to “Degree of T-equivariant maps in ℝⁿ”

An $S^{1}$ -equivariant degree and the Fuller index

Grzegorz Dylawerski, Kazimierz Gęba, Jerzy Jodel, Wacław Marzantowicz (1991)

Annales Polonici Mathematici

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Positivity and Kleiman transversality in equivariant $K$ -theory of homogeneous spaces

Dave Anderson, Stephen Griffeth, Ezra Miller (2011)

Journal of the European Mathematical Society

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We prove the conjectures of Graham–Kumar [GrKu08] and Griffeth–Ram [GrRa04] concerning the alternation of signs in the structure constants for torus-equivariant $K$ -theory of generalized ﬂag varieties $G / P$ . These results are immediate consequences of an equivariant homological Kleiman transversality principle for the Borel mixing spaces of homogeneous spaces, and their subvarieties, under a natural group action with ﬁnitely many orbits. The computation of the coefficients in the expansion...

$Z ₂^{k}$ -actions fixing point ∪ Vⁿ

Pedro L. Q. Pergher (2002)

Fundamenta Mathematicae

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We describe the equivariant cobordism classification of smooth actions $(M^{m}, Φ)$ of the group $G = Z ₂^{k}$ on closed smooth m-dimensional manifolds $M^{m}$ for which the fixed point set of the action is the union F = p ∪ Vⁿ, where p is a point and Vⁿ is a connected manifold of dimension n with n > 0. The description is given in terms of the set of equivariant cobordism classes of involutions fixing p ∪ Vⁿ. This generalizes a lot of previously obtained particular cases of the above question; additionally,...

Stable soliton resolution for equivariant wave maps exterior to a ball

Andrew Lawrie (2014-2015)

Séminaire Laurent Schwartz — EDP et applications

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In this report we review the proof of the stable soliton resolution conjecture for equivariant wave maps exterior to a ball in $ℝ^{3}$ and taking values in the $3$ -sphere. This is joint work with Carlos Kenig, Baoping Liu, and Wilhelm Schlag.

The equivariant universality and couniversality of the Cantor cube

Michael G. Megrelishvili, Tzvi Scarr (2001)

Fundamenta Mathematicae

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Let ⟨G,X,α⟩ be a G-space, where G is a non-Archimedean (having a local base at the identity consisting of open subgroups) and second countable topological group, and X is a zero-dimensional compact metrizable space. Let $⟨ H ({0, 1}^{ℵ ₀}), {0, 1}^{ℵ ₀}, τ ⟩$ be the natural (evaluation) action of the full group of autohomeomorphisms of the Cantor cube. Then (1) there exists a topological group embedding $φ : G ↪ H ({0, 1}^{ℵ ₀})$ ; (2) there exists an embedding $ψ : X ↪ {0, 1}^{ℵ ₀}$ , equivariant with respect to φ, such that ψ(X) is an equivariant retract of ${0, 1}^{ℵ ₀}$ with respect...

Equivariant measurable liftings

Nicolas Monod (2015)

Fundamenta Mathematicae

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We discuss equivariance for linear liftings of measurable functions. Existence is established when a transformation group acts amenably, as e.g. the Möbius group of the projective line. Since the general proof is very simple but not explicit, we also provide a much more explicit lifting for semisimple Lie groups acting on their Furstenberg boundary, using unrestricted Fatou convergence. This setting is relevant to $L^{\infty}$ -cocycles for characteristic classes.

On isomorphisms between fibrations over $T^{k}$ associated with a $T^{k}$ action

Michał Sadowski (1991)

Annales Polonici Mathematici

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Equivariant maps between certain $G$ -spaces with $G = O (n - 1, 1)$ .

Aleksander Misiak, Eugeniusz Stasiak (2001)

Mathematica Bohemica

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In this note, there are determined all biscalars of a system of $s \leq n$ linearly independent contravariant vectors in $n$ -dimensional pseudo-Euclidean geometry of index one. The problem is resolved by finding a general solution of the functional equation $F (A \underset{1}{\to} u, A \underset{2}{\to} u, \dots, A \underset{s}{\to} u) = (sign (det A)) F (\underset{1}{\to} u, \underset{2}{\to} u, \dots, \underset{s}{\to} u)$ for an arbitrary pseudo-orthogonal matrix $A$ of index one and the given vectors $\underset{1}{\to} u, \underset{2}{\to} u, \dots, \underset{s}{\to} u$ .

Classification of homotopy classes of equivariant gradient maps

E. N. Dancer, K. Gęba, S. M. Rybicki (2005)

Fundamenta Mathematicae

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Let V be an orthogonal representation of a compact Lie group G and let S(V),D(V) be the unit sphere and disc of V, respectively. If F: V → ℝ is a G-invariant C¹-map then the G-equivariant gradient C⁰-map ∇F: V → V is said to be admissible provided that ${(\nabla F)}^{- 1} (0) \cap S (V) = \emptyset$ . We classify the homotopy classes of admissible G-equivariant gradient maps ∇F: (D(V),S(V)) → (V,V∖0).

A note on the theorems of Lusternik-Schnirelmann and Borsuk-Ulam

T. E. Barros, C. Biasi (2008)

Colloquium Mathematicae

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Let p be a prime number and X a simply connected Hausdorff space equipped with a free $ℤ_{p}$ -action generated by $f_{p} : X \to X$ . Let $α : S^{2 n - 1} \to S^{2 n - 1}$ be a homeomorphism generating a free $ℤ_{p}$ -action on the (2n-1)-sphere, whose orbit space is some lens space. We prove that, under some homotopy conditions on X, there exists an equivariant map $F : (S^{2 n - 1}, α) \to (X, f_{p})$ . As applications, we derive new versions of generalized Lusternik-Schnirelmann and Borsuk-Ulam theorems.

Equivariant deformation quantization for the cotangent bundle of a flag manifold

Ranee Brylinski (2002)

Annales de l’institut Fourier

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Let $X$ be a (generalized) flag manifold of a complex semisimple Lie group $G$ . We investigate the problem of constructing a graded star product on $ℛ = R (T^{☆} X)$ which corresponds to a $G$ -equivariant quantization of symbols into twisted differential operators acting on half-forms on $X$ . We construct, when $ℛ$ is generated by the momentum functions $μ^{x}$ for $G$ , a preferred choice of $☆$ where $μ^{x} ☆ φ$ has the form $μ^{x} φ + \frac{1}{2} {μ^{x}, φ} t + Λ^{x} (φ) t^{2}$ . Here $Λ^{x}$ are operators on $ℛ$ . In the known examples, $Λ^{x}$ ( $x \neq 0$ ) is not a differential operator, and so the star...

Equivariant K-theory of flag varieties revisited and related results

V. Uma (2013)

Colloquium Mathematicae

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We obtain several several results on the multiplicative structure constants of the T-equivariant Grothendieck ring $K_{T} (G / B)$ of the flag variety G/B. We do this by lifting the classes of the structure sheaves of Schubert varieties in $K_{T} (G / B)$ to R(T) ⊗ R(T), where R(T) denotes the representation ring of the torus T. We further apply our results to describe the multiplicative structure constants of $K {(X)}_{ℚ}$ where X denotes the wonderful compactification of the adjoint group of G, in terms of the structure...

Commuting involutions whose fixed point set consists of two special components

Pedro L. Q. Pergher, Rogério de Oliveira (2008)

Fundamenta Mathematicae

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Let Fⁿ be a connected, smooth and closed n-dimensional manifold. We call Fⁿ a manifold with property when it has the following property: if $N^{m}$ is any smooth closed m-dimensional manifold with m > n and $T : N^{m} \to N^{m}$ is a smooth involution whose fixed point set is Fⁿ, then m = 2n. Examples of manifolds with this property are: the real, complex and quaternionic even-dimensional projective spaces $R P^{2 n}$ , $C P^{2 n}$ and $H P^{2 n}$ , and the connected sum of $R P^{2 n}$ and any number of copies of Sⁿ × Sⁿ, where Sⁿ is the n-sphere...

Noncommutative Borsuk-Ulam-type conjectures

Paul F. Baum, Ludwik Dąbrowski, Piotr M. Hajac (2015)

Banach Center Publications

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Within the framework of free actions of compact quantum groups on unital C*-algebras, we propose two conjectures. The first one states that, if $δ : A \to A ⨂_{m i n} H$ is a free coaction of the C*-algebra H of a non-trivial compact quantum group on a unital C*-algebra A, then there is no H-equivariant *-homomorphism from A to the equivariant join C*-algebra $A ⊛_{δ} H$ . For A being the C*-algebra of continuous functions on a sphere with the antipodal coaction of the C*-algebra of functions on ℤ/2ℤ, we recover the celebrated...

Projectively equivariant quantization and symbol on supercircle $S^{1 | 3}$

Taher Bichr (2021)

Czechoslovak Mathematical Journal

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Let $𝒟_{λ, μ}$ be the space of linear differential operators on weighted densities from $ℱ_{λ}$ to $ℱ_{μ}$ as module over the orthosymplectic Lie superalgebra $𝔬𝔰𝔭 (3 | 2)$ , where $ℱ_{λ}$ , $ł \in ℂ$ is the space of tensor densities of degree $λ$ on the supercircle $S^{1 | 3}$ . We prove the existence and uniqueness of projectively equivariant quantization map from the space of symbols to the space of differential operators. An explicite expression of this map is also given.

Equivariant algebraic topology

Sören Illman (1973)

Annales de l'institut Fourier

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Let $G$ be a topological group. We give the existence of an equivariant homology and cohomology theory, defined on the category of all $G$ -pairs and $G$ -maps, which both satisfy all seven equivariant Eilenberg-Steenrod axioms and have a given covariant and contravariant, respectively, coefficient system as coefficients. In the case that $G$ is a compact Lie group we also define equivariant $C W$ -complexes and mention some of their basic properties. The paper is a short abstract...