Now showing items 166-185 of 245

    • Icon

      Obtaining combinatorial structures associated with low-dimensional Leibniz algebras  [Presentation]

      Ceballos González, Manuel; Núñez Valdés, Juan; Tenorio Villalón, Ángel Francisco (2013)
      In this paper, we analyze the relation between Leibniz algebras and combinatorial structures. More concretely, we study ...
    • Icon

      On abelian subalgebras and ideals of maximal dimension in supersolvable Lie algebras  [Article]

      Ceballos González, Manuel; Towers, David A. (Elsevier, 2014-02)
      In this paper, the main objective is to compare the abelian subalgebras and ideals of maximal dimension for finite-dimensional ...
    • Icon

      On certain anti-invariant submanifolds of an S-manifold  [Article]

      Cabrerizo Jaraíz, José Luis; Fernández Fernández, Luis Manuel (Sociedade Portuguesa de Matemática, 1993)
      In this paper, the geometry of certain anti-invariant submanifolds of an S-manifold, namely those which are normal to the structure vector fields, is studied.
    • Icon

      On generalized Sasakian-space-forms  [Presentation]

      Carriazo Rubio, Alfonso; Blair, David E.; Alegre Rueda, Pablo Sebastián (2004)
      We study contact metric and trans-Sasakian generalized Sasakian-space-forms. We also give some interesting examples of generalized Sasakian-space-forms by using warped products and conformal changes of metric.
    • Icon

      On manifolds with nonhomogeneous factors  [Article]

      Cárdenas Escudero, Manuel Enrique; Fernández Lasheras, Francisco Jesús; Quintero Toscano, Antonio Rafael; Repovš, Dušan (Springer, 2012-06)
      We present simple examples of finite-dimensional connected homogeneous spaces (they are actually topological manifolds) ...
    • Icon

      On pseudo-Einstein hypersurfaces of ℋ2n+s  [Article]

      Cabrerizo Jaraíz, José Luis; Fernández Fernández, Luis Manuel; Fernández Andrés, Manuel (Indian National Science Academy, 1996-05)
      In this paper, some properties of the geometry of pseudo-Einstein hypersurfaces of the S-manifold ℋ 2n+s are studied and a theorem concerning their principal curvatures is obtained.
    • Icon

      On slant submanifolds of neutral Kaehler manifolds  [Article]

      Arslan, Kadri; Carriazo Rubio, Alfonso; Chen, Bang-Yen; Murathan, Cengizhan (Mathematical Society of the Republic of China, 2010-04)
      An indefinite Riemannian manifold is called neutral it its index is equal to one half of its dimension and an indefinite ...
    • Icon

      On surfaces in digital topology  [Presentation]

      Ayala Gómez, Rafael; Domínguez Murillo, Eladio; Francés Román, Ángel Ramón; Quintero Toscano, Antonio Rafael; Rubio Sender, Julio (1995)
      In R. Ayala, E. Domínguez, A.R. Francés, A. Quintero, J. Rubio. A Polyhedral Approach to Digital Topology a new framework ...
    • Icon

      On the classifying space for proper actions of groups with cyclic torsion  [Article]

      Antolín Pichel, Yago; Flores Díaz, Ramón Jesús (De Gruyter, 2014-01)
      In this paper we introduce a common framework for describing the topological part of the Baum-Connes conjecture for a ...
    • Icon

      On the connectivity of skeletons of pseudomanifolds with boundary  [Article]

      Ayala Gómez, Rafael; Chávez de Diego, María José; Márquez Pérez, Alberto; Quintero Toscano, Antonio Rafael (Mathematical Institute, Academy of Sciences of the Czech Republic, 2002)
      In this note we show that 1-skeletons and 2-skeletons of n-pseudomanifolds with full boundary are (n+ 1)-connected graphs and n-connected 2-complexes, respectively. This generalizes previous results due to Barnette and Woon.
    • Icon

      On the existence of almost contact structure and the contact magnetic field  [Article]

      Cabrerizo Jaraíz, José Luis; Fernández Andrés, Manuel; Gómez Casanueva, Juan Salvador (Springer, 2009-10)
      In this short note we give a simple proof of the existence of an almost contact metric structure on any orientable ...
    • Icon

      On the Freudenthal extensions of proper confluent maps  [Article]

      Charatonik, Wlodzimierz J; Fernández Bayort, Tomás; Quintero Toscano, Antonio Rafael (University of Houston, 2012)
      In this paper we study when Freudenthal extensions of proper maps preserve the (weak, semi) confluency. Also the extensions to the Alexandroff one-point compactificaton are considered.
    • Icon

      On the idempotency of some composite functors  [Article]

      Flores Díaz, Ramón Jesús (Springer, 2012-01)
      We present examples of localization functors whose composition with certain cellularization functors is not idempotent, and vice versa.
    • Icon

      On the locally finite chain algebra of a proper homotopy type  [Article]

      Baues, Hans Joachim; Quintero Toscano, Antonio Rafael (Belgian Mathematical Society, 1996)
      In the classical paper [A-H] Adams-Hilton constructed a free chain algebra which is an important algebraic model of a ...
    • Icon

      On the topology of locally 2-connected Peano continua  [Article]

      Chávez de Diego, María José; Fernández Bayort, Tomás; Quintero Toscano, Antonio Rafael; Villar Liñán, María Trinidad (Rocky Mountain Mathematics Consortium, 2012)
      Several recent results by Thomassen ([23 The locally connected compatc metric spaces embeddable in the plane, Combinatorica ...
    • Icon

      On totally geodesic invariant submanifolds of an S-manifold  [Article]

      Fernández Fernández, Luis Manuel (Real Academia de Ciencias de Zaragoza, 1988)
      In [1] Blair, O.E.: 1970, J. Diff. Geom. 4, (155-167), S-manifolds, which reduce in a special case to Sasakian manifolds, ...
    • Icon

      On ξ-conformally flat contact metric manifolds  [Article]

      Zhen, Guo; Cabrerizo Jaraíz, José Luis; Fernández Fernández, Luis Manuel; Fernández Andrés, Manuel (Indian National Science Academy, 1997-06)
      In this paper, the notion of ξ-conformally flat on a contact metric structure is introduced and it is proved that any ...
    • Icon

      One-relator groups and proper 3-realizability  [Article]

      Cárdenas Escudero, Manuel Enrique; Fernández Lasheras, Francisco Jesús; Quintero Toscano, Antonio Rafael; Repovš, Dušan (European Mathematical Society, 2009)
      How different is the universal cover of a given finite 2-complex from a 3-manifold (from the proper homotopy viewpoint)? ...
    • Icon

      Optimal inequalities, contact delta-invariants and their applications  [Article]

      Chen, Bang-Yen; Martín Molina, Verónica (Malaysian Mathematical Sciences Society, 2013)
      Associated with a k-tuple (n1, . . . , nk) ∈ S(2n + 1) with n ≥ 1, we define a contact δ-invariant, δc (n1, . . . , nk), ...
    • Icon

      El papel de las webquest en las NTIC  [Presentation]

      Falcón Ganfornina, Óscar Jesús; Falcón Ganfornina, Raúl Manuel; Núñez Valdés, Juan; Tenorio Villalón, Ángel Francisco (2008-07)
      La ponencia que aquí se presenta persigue un triple objetivo. Por una parte, mostrarle al lector en general, y al profesorado ...