Exotic Deformations of Calabi-Yau Manifolds
Paolo de Bartolomeis, Adriano Tomassini (2013)
Annales de l’institut Fourier
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We introduce
Paolo de Bartolomeis, Adriano Tomassini (2013)
Annales de l’institut Fourier
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We introduce
Stefan Rolewicz (2009)
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
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In the paper a class of families (M) of functions defined on differentiable manifolds M with the following properties: . if M is a linear manifold, then (M) contains convex functions, . (·) is invariant under diffeomorphisms, . each f ∈ (M) is differentiable on a dense -set, is investigated.
Laurent Meersseman (2011)
Annales scientifiques de l'École Normale Supérieure
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Consider the following uniformization problem. Take two holomorphic (parametrized by some analytic set defined on a neighborhood of in , for some ) or differentiable (parametrized by an open neighborhood of in , for some ) deformation families of compact complex manifolds. Assume they are pointwise isomorphic, that is for each point of the parameter space, the fiber over of the first family is biholomorphic to the fiber over of the second family. Then, under which conditions...
Pedro L. Q. Pergher, Rogério de Oliveira (2005)
Fundamenta Mathematicae
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Let Fⁿ be a connected, smooth and closed n-dimensional manifold satisfying the following property: if is any smooth and closed m-dimensional manifold with m > n and is a smooth involution whose fixed point set is Fⁿ, then m = 2n. We describe the equivariant cobordism classification of smooth actions of the group on closed smooth m-dimensional manifolds for which the fixed point set of the action is a submanifold Fⁿ with the above property. This generalizes a result of F....
J. H. Rieger, M. A. S. Ruas, R. Wik Atique (2008)
Banach Center Publications
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A stable deformation of a real map-germ is said to be an M-deformation if all isolated stable (local and multi-local) singularities of its complexification are real. A related notion is that of a good real perturbation of f (studied e.g. by Mond and his coworkers) for which the homology of the image (for n < p) or discriminant (for n ≥ p) of coincides with that of . The class of map germs having an M-deformation is, in some sense, much larger than the one having a good...
Jean Roydor (2007)
Banach Center Publications
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We describe the subspaces of (1 ≤ p ≠ 2 < ∞) which are the range of a completely contractive projection.
Nicolas Monod, Henrik Densing Petersen (2014)
Annales de l’institut Fourier
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Let be any group containing an infinite elementary amenable subgroup and let . We construct an exhaustion of by closed invariant subspaces which all intersect trivially a fixed non-trivial closed invariant subspace. This is an obstacle to -dimension and gives an answer to a question of Gaboriau.
Jean-François Bony, Dietrich Häfner (2012)
Annales scientifiques de l'École Normale Supérieure
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Let be a long range metric perturbation of the Euclidean Laplacian on , . We prove local energy decay for the solutions of the wave, Klein-Gordon and Schrödinger equations associated to . The problem is decomposed in a low and high frequency analysis. For the high energy part, we assume a non trapping condition. For low (resp. high) frequencies we obtain a general result about the local energy decay for the group where has a suitable development at zero (resp. infinity). ...
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 is any smooth closed m-dimensional manifold with m > n and 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 , and , and the connected sum of and any number of copies of Sⁿ × Sⁿ, where Sⁿ is the n-sphere...
Edoardo Ballico, Riccardo Ghiloni (2014)
Annales Polonici Mathematici
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Let V be a real algebraic manifold of positive dimension. The aim of this paper is to show that, for every integer b (arbitrarily large), there exists a trivial Nash family of real algebraic manifolds such that V₀ = V, is an algebraic family of real algebraic manifolds over (possibly singular over y = 0) and is perfectly parametrized by in the sense that is birationally nonisomorphic to for every with y ≠ z. A similar result continues to hold if V is a singular real algebraic...
W. M. Mikulski (2002)
Colloquium Mathematicae
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Let r and n be natural numbers. For n ≥ 2 all natural operators transforming vector fields on n-manifolds M to 1-forms on are classified. For n ≥ 3 all natural operators transforming vector fields on n-manifolds M to 2-forms on are completely described.
Zhiqi Chen, Jifu Li, Ming Ding (2022)
Czechoslovak Mathematical Journal
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-manifold algebras are focused on the algebraic properties of the tangent sheaf of -manifolds. The local classification of 3-dimensional -manifolds has been given in A. Basalaev, C. Hertling (2021). We study the classification of 3-dimensional -manifold algebras over the complex field .
Christian Bonatti, Sylvain Crovisier, Gioia M. Vago, Amie Wilkinson (2008)
Annales scientifiques de l'École Normale Supérieure
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Given any compact manifold , we construct a non-empty open subset of the space of -diffeomorphisms and a dense subset such that the centralizer of every diffeomorphism in is uncountable, hence non-trivial.
Simon Lücking (2014)
Studia Mathematica
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Let G be an infinite, compact abelian group and let Λ be a subset of its dual group Γ. We study the question which spaces of the form or and which quotients of the form or have the Daugavet property. We show that is a rich subspace of C(G) if and only if is a semi-Riesz set. If is a rich subspace of L¹(G), then is a rich subspace of C(G) as well. Concerning quotients, we prove that has the Daugavet property if Λ is a Rosenthal set, and that is a poor subspace of L¹(G)...
Wei Wang (2003)
Journal of the European Mathematical Society
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We construct the CR invariant canonical contact form on scalar positive spherical CR manifold , which is the CR analogue of canonical metric on locally conformally flat manifold constructed by Habermann and Jost. We also construct another canonical contact form on the Kleinian manifold , where is a convex cocompact subgroup of and is the discontinuity domain of . This contact form can be used to prove that is scalar positive (respectively, scalar negative, or scalar vanishing)...
Yasushi Hirata, Nobuyuki Kemoto (2003)
Fundamenta Mathematicae
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It is known that all subspaces of ω₁² have the property that every pair of disjoint closed sets can be separated by disjoint -sets (see [4]). It has been conjectured that all subspaces of ω₁ⁿ also have this property for each n < ω. We exhibit a subspace of ⟨α,β,γ⟩ ∈ ω₁³: α ≤ β ≤ γ which does not have this property, thus disproving the conjecture. On the other hand, we prove that all subspaces of ⟨α,β,γ⟩ ∈ ω₁³: α < β < γ have this property.
Sergey V. Astashkin, Lech Maligranda (2015)
Studia Mathematica
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The structure of the closed linear span of the Rademacher functions in the Cesàro space is investigated. It is shown that every infinite-dimensional subspace of either is isomorphic to l₂ and uncomplemented in , or contains a subspace isomorphic to c₀ and complemented in . The situation is rather different in the p-convexification of if 1 < p < ∞.
Teo Mora (1989)
Publications mathématiques et informatique de Rennes
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Maciej Paluszyński (2010)
Colloquium Mathematicae
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We consider the subspace of L²(ℝ) spanned by the integer shifts of one function ψ, and formulate a condition on the family , which is equivalent to the weight function being > 0 a.e.
Parameswaran Sankaran, Ajay Singh Thakur (2013)
Annales de l’institut Fourier
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Let be a holomorphic line bundle over a compact complex manifold for . Let denote the associated principal circle-bundle with respect to some hermitian inner product on . We construct complex structures on which we refer to as
A. Pełczyński, H. Rosenthal (1975)
Studia Mathematica
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Dibakar Dey, Pradip Majhi (2021)
Communications in Mathematics
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The object of the present paper is to study some types of semisymmetry conditions on two classes of almost Kenmotsu manifolds. It is shown that a -almost Kenmotsu manifold satisfying the curvature condition is locally isometric to the hyperbolic space . Also in -almost Kenmotsu manifolds the following conditions: (1) local symmetry , (2) semisymmetry , (3) , (4) , (5) locally isometric to the hyperbolic space are equivalent. Further, it is proved that a -almost Kenmotsu manifold...
José F. Fernando, José Manuel Gamboa, Jesús M. Ruiz (2014)
Journal of the European Mathematical Society
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We study here several finiteness problems concerning affine Nash manifolds and Nash subsets . Three main results are: (i) A Nash function on a semialgebraic subset of has a Nash extension to an open semialgebraic neighborhood of in , (ii) A Nash set that has only normal crossings in can be covered by finitely many open semialgebraic sets equipped with Nash diffeomorphisms such that , (iii) Every affine Nash manifold with corners is a closed subset of an affine Nash...
Yan Zhao, Ximin Liu (2019)
Czechoslovak Mathematical Journal
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We give the definition of -biminimal submanifolds and derive the equation for -biminimal submanifolds. As an application, we give some examples of -biminimal manifolds. Finally, we consider -minimal hypersurfaces in the product space and derive two rigidity theorems.