1,721,001 research outputs found
The Rossi-Vergne theorem and constant coefficient PDEs on the Heisenberg group
No full textQuaderni di Matematica,
On the curvature of metric contact pairs
No full textWe consider manifolds endowed with metric contact pairs for which the two characteristic foliations are orthogonal. We give some properties of the curvature tensor and in particular a formula for the Ricci curvature in the direction of the sum of the two Reeb vector fields. This shows that metrics associated to normal contact pairs cannot be flat. Therefore flat non-Kahler Vaisman manifolds do not exist. Furthermore we give a local classification of metric contact pair manifolds whose curvature vanishes on the vertical subbundle. As a corollary we have that flat associated metrics can only exist if the leaves of the characteristic foliations are at most three-dimensional
Symmetry in the geometry of metric contact pairs
No full textWe prove that the universal covering of a complete locally symmetric normal metric contact pair manifold with decomposable φ{symbol} is a Calabi-Eckmann manifold or the Riemannian product of a sphere and R. We show that a complete, simply connected, normal metric contact pair manifold with decomposable φ{symbol}, such that the foliation induced by the vertical subbundle is regular and reflections in the integral submanifolds of the vertical subbundle are isometries, is the product of globally φ{symbol}-symmetric spaces or the product of a globally φ{symbol}-symmetric space and R. Moreover in the first case the manifold fibers over a locally symmetric space endowed with a symplectic pair
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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