102,635 research outputs found
G. B. Montini Substitut Secretary of State (in tandem with Domenico Tardini)
No full textGraham Robert A. G. B. Montini Substitut Secretary of State (in tandem with Domenico Tardini). In: Paul VI et la modernité dans l'Église. Actes du colloque de Rome (2-4 juin 1983) Rome : École Française de Rome, 1984. pp. 67-84. (Publications de l'École française de Rome, 72
HKT MANIFOLDS: HODGE THEORY, FORMALITY AND BALANCED METRICS
No full textLet be a compact HKT manifold, and let us denote with the conjugate Dolbeault operator with respect to I, \partial_J:=J<^>{-1}\overline\partial J, \partial<^>\Lambda:=[\partial,\Lambda], where Lambda is the adjoint of . Under suitable assumptions, we study Hodge theory for the complexes (A<^>{\bullet,0},\partial,\partial_J) and (A<^>{\bullet,0},\partial,\partial<^>\Lambda) showing a similar behavior to Kahler manifolds. In particular, several relations among the Laplacians, the spaces of harmonic forms and the associated cohomology groups, together with Hard Lefschetz properties, are proved. Moreover, we show that for a compact HKT -manifold, the differential graded algebra (A<^>{\bullet,0},\partial) is formal and this will lead to an obstruction for the existence of an HKT structure on a compact complex manifold (M, I). Finally, balanced HKT structures on solvmanifolds are studied
G. B. Montini Substitut Secretary of State (in tandem with Domenico Tardini)
No full textGraham Robert A. G. B. Montini Substitut Secretary of State (in tandem with Domenico Tardini). In: Paul VI et la modernité dans l'Église. Actes du colloque de Rome (2-4 juin 1983) Rome : École Française de Rome, 1984. pp. 67-84. (Publications de l'École française de Rome, 72
∂-Harmonic forms on 4-dimensional almost-Hermitian manifolds
No full textLet (X, J) be a 4-dimensional compact almost-complex manifold and let g be a Hermitian metric on (X, J). Denote by ∆∂ := ∂∂∗ + ∂∗∂ the ∂-Laplacian. If g is globally conformally Kähler, respectively (strictly) locally conformally Kähler, we prove that the dimension of the space of ∂-harmonic (1, 1)-forms on X, denoted as h∂1,1, is a topological invariant given by b− + 1, respectively b−. As an application, we provide a one-parameter family of almost-Hermitian structures on the Kodaira-Thurston manifold for which such a dimension is b−. This gives a positive answer to a question raised by T. Holt and W. Zhang. Furthermore, the previous example shows that h1∂,1 depends on the metric, answering to a Kodaira and Spencer’s problem. Notice that such almost-complex manifolds admit both almost-Kähler and (strictly) locally conformally Kähler metrics and this fact cannot occur on compact complex manifolds
Almost-complex invariants of families of six-dimensional solvmanifolds
No full textWe compute almost-complex invariants hδ ̄p,o, hDolp,o and almost-Hermitian invariants hδ ̄p,o on families of almost-Kähler and almost-Hermitian 6-dimensional solvmanifolds. Finally, as a consequence of almost-Kähler identities we provide an obstruction to the existence of a compatible symplectic structure on a given compact almost-complex manifold. Notice that, when (X, J, g, ω) is a compact almost Hermitian manifold of real dimension greater than four, not much is known concerning the numbers hδ ̄p,q
Symplectic cohomologies and deformations
No full textIn this note we study the behavior of symplectic cohomology groups under symplectic deformations. Moreover, we show that for compact almost-Kähler manifolds (X, J, g, ω) with JC∞-pure and full the space of de Rham harmonic forms is contained in the space of symplectic-Bott-Chern harmonic forms. Furthermore, we prove that the second non-HLC degree measures the gap between the de Rham and the symplectic-Bott-Chern harmonic forms
Complex symplectic Lie algebras with large Abelian subalgebras
No full textWe present two constructions of complex symplectic structures on Lie algebras with large Abelian ideals. In particular, we completely classify complex symplectic structures on almost Abelian Lie algebras. By considering compact quotients of their corresponding connected, simply connected Lie groups we obtain many examples of complex symplectic manifolds which do not carry (hyper)kahler metrics. We also produce examples of compact complex symplectic manifolds endowed with a fibration whose fibers are Lagrangian tori.(c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons .org /licenses /by -nc -nd /4 .0/)
Idoneo... fino a prova contraria: una diagnosi precoce di cardiomiopatia ipertrofica emersa dalla collaborazione tra Medico e Cardiologo dello Sport
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