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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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3469103137 · Jun 202019922001200920172026
48 results for Complexified Actions

Study of complexified Hermitian symmetric spaces and their structures.

problem Understanding the hyperkähler structures and symplectic properties of complexified Hermitian symmetric spaces.
method Explicit diffeomorphisms and moment-critical subsets analysis.
result Almost all complex and symplectic structures are equivalent to the ones on G/KG/K and $T^*\left(G_u/K_0 ight)$ respectively.

We first investigate the geometry of orbits of the isotropy action on a semi-simple pseudo-Riemannian symmetric space by investigating the complexified action. Next we investigate the geometry of the orbits of Hermann type actions on the symmetric spaces. By considering two special Hermann type actions on the symmetric…

2008-07-10abs ↗pdf ↗

We prove that a K-contact Lie group of dimension five or greater is the central extension of a symplectic Lie group by complexifying the Lie algebra and applying a result from complex contact geometry, namely, that, if the adjoint action of the complex Reeb vector field on a complex contact Lie algebra is diagonalizabl…

2010-06-08abs ↗pdf ↗

Study norm-squared of momentum map in infinite dimensions with applications to symplectic geometry.

problem Understanding the norm-squared of the momentum map in infinite-dimensional settings.
method Calculation of Hessian, decomposition of stabilizer, application to symplectic and complex structures.
result Positive semi-definiteness of Hessian along complexified orbit and new central extensions of symplectomorphism group.

Study on Hermitian Calabi functional in complexified orbits of symplectic manifolds.

problem Analyzing the Hermitian Calabi functional on complexified orbits of symplectic manifolds.
method Explicit formula for Hessian of Hermitian Calabi functional, semi-positive definiteness proof, and weak parabolicity of Hermitian Calabi flow.
result Hessian of Hermitian Calabi functional is semi-positive definite on complexified orbits.

We shall construct a natural Higgs bundle structure on the complexified Kähler cone of a compact Kähler manifold, which can be seen as an analogy of the classical Higgs bundle structure associated to a variation of Hodge structure. In the proof of the flat-ness of our Higgs bundle, we find a commutator identity that ca…

2016-12-07abs ↗pdf ↗

New combinatorial model for Milnor fibration using oriented matroids.

problem Understanding the homotopy type of Milnor fibers of complexified real arrangements.
method Introducing a poset quasi-fibration based on a subdivision of the Salvetti complex and an oriented matroid.
result Homotopy type of Milnor fiber depends only on the combinatorial structure of the oriented matroid.

We give geometric explanations and proofs of various mirror symmetry conjectures for TnT^{n}-invariant Calabi-Yau manifolds when instanton corrections are absent. This uses fiberwise Fourier transformation together with base Legendre transformation. We discuss mirror transformations of (i) moduli spaces of complex stru…

2000-09-27abs ↗pdf ↗

Let M be a Kaehler manifold with a free, holomorphic and Hamiltonian action of the standard n-torus T. We give a simple, explicit and canonical formula for the Kaehler potential on the Kaehler reduction of M. As a consequence we can derive improvements of several classical results known for more general Hamiltonian red…

2003-02-27abs ↗pdf ↗

Criterion for polystability in Lie group actions on manifolds.

problem Characterizing orbits intersecting a specific set in Lie group actions.
method Hilbert-Mumford criterion applied to polystability, using Cartan decomposition and gradient maps.
result Characterization of orbits intersecting a specific set in terms of maximal weight functions.

The paper constructs homotopically non-trivial spheres in complexified spaces.

problem Embedding spheres in complexified spaces defined by hyperplane arrangements.
method Introducing locally consistent systems of half-spaces, embedding a sphere, and computing twisted intersection numbers.
result The constructed sphere is homotopically non-trivial if the half-space system is globally consistent.

For a real oriented hyperplane arrangement, we show that the corresponding Salvetti complex is homotopy equivalent to the complement of the complexified arrangement. This result was originally proved by M. Salvetti. Our proof follows the framework of a proof given by L. Paris and relies heavily on the notation of orien…

2009-05-27abs ↗pdf ↗

Forty-six years after the birth of supersymmetry in 1973 from works of Julius Wess and Bruno Zumino, the standard quantum-field-theorists and particle physicists' language of `superspaces', `supersymmetry', and `supersymmetric action functionals in superspace formulation' as given in Chapters IV, V, VI, VII, XXII of th…

2020-02-27abs ↗pdf ↗

We study hamiltonian actions of compact groups in the presence of compatible involutions. We show that the lagrangian fixed point set on the symplectically reduced space is isomorphic to the disjoint union of the involutively reduced spaces corresponding to involutions on the group strongly inner to the given one. Our …

2003-03-26abs ↗pdf ↗

The reduced Burau representation VnV_n of the braid group BnB_n is obtained from the action of BnB_n on the homology of an infinite cyclic cover of the disc with nn punctures. The group homology H(Bn;Vn)H_*(B_n;V_n) of braid groups with coefficients in the complexified reduced Burau representation is calculated. Our topolog…

2015-06-06abs ↗pdf ↗

We find the T-duality transformation rules for 2-dimensional (2,1) supersymmetric sigma-models in (2,1) superspace. Our results clarify certain aspects of the (2,1) sigma model geometry relevant to the discussion of T-duality. The complexified duality transformations we find are equivalent to the usual Buscher duality …

2019-01-03abs ↗pdf ↗

The paper develops stability criteria for real reductive Lie groups acting on manifolds.

problem Analyzing stability of real reductive Lie group actions on manifolds.
method Introduced a gradient map and maximal weight function to characterize stability conditions.
result Characterized stability, semistability, and polystability using numerical criteria.

Let VV be a finite dimensional complex vector space and $W\subseteq \GL(V)$ be a finite complex reflection group. Let $V^{\reg}$ be the complement in VV of the reflecting hyperplanes. We prove that $V^{\reg}$ is a K(π,1)K(π,1) space. This was predicted by a classical conjecture, originally stated by Brieskorn for complex…

2006-10-26abs ↗pdf ↗

Subharmonicity of Dirichlet energy proven for Kähler manifolds.

problem Subharmonicity of Dirichlet energy in Kähler families.
method Polarized family of compact Kähler manifolds, pluriharmonic maps, nonpositive complexified sectional curvature.
result Dirichlet energy is subharmonic in the parameter space.

Given a compact Lie group, endowed with a bi-invariant Riemannian metric, its complexification inherits a Kaehler structure having twice the kinetic energy of the metric as its potential, and Kaehler reduction with reference to the adjoint action yields a stratified Kaehler structure on the resulting adjoint quotient. …

2004-04-06abs ↗pdf ↗

Let VV be a finite dimensional complex vector space and $W\subset \GL(V)$ be a finite complex reflection group. Let $V^{\reg}$ be the complement in VV of the reflecting hyperplanes. A classical conjecture predicts that $V^{\reg}$ is a K(pi,1)K(pi,1) space. When WW is a complexified real reflection group, the conjecture f…

2004-11-29abs ↗pdf ↗

We study the gradient flow lines of a Yang-Mills-type functional on the space of gauged holomorphic maps H(P,X)\mathcal{H}(P,X), where PP is a principal bundle on a Riemann surface ΣΣ and XX is a Kähler Hamiltonian GG-manifold. For compact ΣΣ, possibly with boundary, we prove long time existence of the gradient flow. …

2012-01-09abs ↗pdf ↗

Study of dHYM connections on ruled surfaces with variable background metrics.

problem Finding new dHYM connections on ruled surfaces with variable metrics.
method Using momentum construction and moment map partial differential equations, coupled to scalar curvature of the background.
result Provide many new examples of dHYM connections coupled to a variable background Kähler metric.

We prove the existence of lattice isomorphic line arrangements having π1π_1-equivalent or homotopy-equivalent complements and non homeomorphic embeddings in the complex projective plane. We also provide two explicit examples, one is formed by real-complexified arrangements while the second is not.

2018-01-08abs ↗pdf ↗

New theory connects string theory to swampland distance conjecture.

problem Connecting string theory to swampland distance conjecture.
method Deformations of the heterotic superpotential, treating separately for large fluxes or large distances, integrating out fields to obtain a new field theory.
result New holomorphic theory defined, connects to swampland distance conjecture.

The paper constructs a free abelian group from Anosov representations on bundles.

problem Constructing a free abelian group from Anosov representations on bundles.
method Extending the Γ\Gamma-action via ρ\rho to the space of connections on pullbacks of tangent bundles.
result A free abelian group FabF^{ab} is constructed and acts properly discontinuously on it.

Every finite dimensional real representation of a compact real semisimple Lie algebra determines a metric 2-step nilpotent Lie algebra and a corresponding simply connected metric 2-step nilpotent Lie group N. We study the differential geometry of N using representation theory of the complexified complex semisimple Lie …

2008-06-17abs ↗pdf ↗

We represent algebraic curves via commuting matrix polynomials. This allows us to show that the Hilbert scheme of cohomologically stable twisted rational curves of degree dd in P3\P1{\Bbb P}^3\backslash {\Bbb P}^1 is isomorphic to a complexified hyperkähler quotient of an open subset of a vector space by a non-reductive …

2019-03-05abs ↗pdf ↗

Constructs maps from field theories to complexified K-theory and elliptic cohomology.

problem Identifying geometric models for Chern characters in supersymmetric field theories.
method Higher-dimensional generalization of Fei Han's method, involving super moduli spaces and derived geometry.
result Provides evidence for the Stolz--Teichner program and geometric models for Chern characters.