Exotic Deformations of Calabi-Yau Manifolds
Paolo de Bartolomeis, Adriano Tomassini (2013)
Annales de l’institut Fourier
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We introduce
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Paolo de Bartolomeis, Adriano Tomassini (2013)
Annales de l’institut Fourier
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We introduce
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....
Shyamal Kumar Hui, Debabrata Chakraborty (2016)
Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica
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The object of the present paper is to study -Ricci solitons on -Einstein -manifolds. It is shown that if is a recurrent torse forming -Ricci soliton on an -Einstein -manifold then is (i) concurrent and (ii) Killing vector field.
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.
David L. Wehlau (2013)
Journal of the European Mathematical Society
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Let be any field of characteristic . It is well-known that there are exactly inequivalent indecomposable representations of defined over . Thus if is any finite dimensional -representation there are non-negative integers such that . It is also well-known there is a unique (up to equivalence) dimensional irreducible complex representation of given by its action on the space of forms. Here we prove a conjecture, made by R. J. Shank, which reduces the computation...
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...
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 .
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...
Alan S. Dow, Saharon Shelah (2023)
Commentationes Mathematicae Universitatis Carolinae
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The cardinal invariants of are known to satisfy that . We prove that all inequalities can be strict. We also introduce a new upper bound for and show that it can be less than . The key method is to utilize finite support matrix iterations of ccc posets following paper Ultrafilters with small generating sets by A. Blass and S. Shelah (1989).
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
Rafał Lutowski, Andrzej Szczepański (2013)
Fundamenta Mathematicae
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Let M be a flat manifold. We say that M has the property if the Reidemeister number R(f) is infinite for every homeomorphism f: M → M. We investigate relations between the holonomy representation ρ of M and the property. When the holonomy group of M is solvable we show that if ρ has a unique ℝ-irreducible subrepresentation of odd degree then M has the property. This result is related to Conjecture 4.8 in [K. Dekimpe et al., Topol. Methods Nonlinear Anal. 34 (2009)].
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...
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.
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...
B. Balcar, F. Hernández-Hernández, M. Hrušák (2004)
Fundamenta Mathematicae
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We study combinatorial properties of the partial order (Dense(ℚ),⊆). To do that we introduce cardinal invariants , , , , , describing properties of Dense(ℚ). These invariants satisfy ≤ ℚ ≤ ℚ ≤ ℚ ≤ ℚ ≤ ℚℚ = pℚ = tℚ = iℚ > hℚ > rnon(M)=min||: ⊆ Dense(R) ∧ (∀I ∈ nwd(R))(∃D ∈ )(I ∩ D = ∅) and cof(M) = min||: ⊆ Dense(ℚ) ∧ (∀I ∈ nwd)(∃D ∈ )(I ∩ = ∅). We use these facts to show that cof(M) ≤ i, which improves a result of S. Shelah.
Adel Bilal (1997)
Recherche Coopérative sur Programme n°25
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Józef H. Przytycki, Witold Rosicki (2014)
Banach Center Publications
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We consider the classical problem of a position of n-dimensional manifold Mⁿ in . We show that we can define the fundamental (n+1)-cycle and the shadow fundamental (n+2)-cycle for a fundamental quandle of a knotting . In particular, we show that for any fixed quandle, quandle coloring, and shadow quandle coloring, of a diagram of Mⁿ embedded in we have (n+1)- and (n+2)-(co)cycle invariants (i.e. invariant under Roseman moves).
Cinzia Casagrande (2012)
Annales scientifiques de l'École Normale Supérieure
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Let be a complex Fano manifold of arbitrary dimension, and a prime divisor in . We consider the image of in under the natural push-forward of -cycles. We show that . Moreover if , then either where is a Del Pezzo surface, or and has a fibration in Del Pezzo surfaces onto a Fano manifold such that .
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)...
Michael Usher (2014)
Annales de la faculté des sciences de Toulouse Mathématiques
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For a Morse function on a compact oriented manifold , we show that has more critical points than the number required by the Morse inequalities if and only if there exists a certain class of link in whose components have nontrivial linking number, such that the minimal value of on one of the components is larger than its maximal value on the other. Indeed we characterize the precise number of critical points of in terms of the Betti numbers of and the behavior of with respect...
Jan Kurek, Włodzimierz M. Mikulski (2012)
Annales Polonici Mathematici
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We prove that the problem of finding all -natural operators lifting classical linear connections ∇ on m-manifolds M to classical linear connections on the Weil bundle corresponding to a p-dimensional (over ℝ) Weil algebra A is equivalent to the one of finding all -natural operators transforming classical linear connections ∇ on m-manifolds M into base-preserving fibred maps .
Jan Kurek, Włodzimierz M. Mikulski (2011)
Annales Polonici Mathematici
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We extend the concept of r-order connections on fibred manifolds to the one of (r,s,q)-order projectable connections on fibred-fibred manifolds, where r,s,q are arbitrary non-negative integers with s ≥ r ≤ q. Similarly to the fibred manifold case, given a bundle functor F of order r on (m₁,m₂,n₁,n₂)-dimensional fibred-fibred manifolds Y → M, we construct a general connection ℱ(Γ,Λ):FY → J¹FY on FY → M from a projectable general (i.e. (1,1,1)-order) connection on Y → M by means of an...