Ara es mostren els items 37-51 de 51

    • Separating bichromatic point sets in the plane by restricted orientation convex hulls 

      Alegría Galicia, Carlos; Orden Martin, David; Seara Ojea, Carlos; Urrutia Galicia, Jorge (2023-04-01)
      Article
      Accés obert
      We explore the separability of point sets in the plane by a restricted-orientation convex hull, which is an orientation-dependent, possibly disconnected, and non-convex enclosing shape that generalizes the convex hull. Let ...
    • Some structural, metric and convex properties of the boundary of a graph 

      Hernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio Manuel; Seara Ojea, Carlos (2013-04-25)
      Article
      Accés obert
      Let u;v be two vertices of a connected graph G . The vertex v is said to be a boundary vertex of u if no neighbor of v is further away from u than v . The boundary of a graph is the set of all its ...
    • Stabbers of line segments in the plane 

      Claverol Aguas, Mercè; Garijo, Delia; Grima, Clara; Márquez, Alberto; Seara Ojea, Carlos (2011-07)
      Article
      Accés obert
      The problem of computing a representation of the stabbing lines of a set S of segments in the plane was solved by Edelsbrunner et al. We provide efficient algorithms for the following problems: computing the stabbing wedges ...
    • Stabbing circles for sets of segments in the plane 

      Claverol Aguas, Mercè; Khramtcova, Elena; Papadopoulou, Evanthia; Saumell, Maria; Seara Ojea, Carlos (2016)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      Stabbing a set S of n segments in the plane by a line is a well-known problem. In this paper we consider the variation where the stabbing object is a circle instead of a line. We show that the problem is tightly connected ...
    • Stabbing circles for sets of segments in the plane 

      Claverol Aguas, Mercè; Khramtcova, Elena; Papadopoulou, Evanthia; Saumell, Maria; Seara Ojea, Carlos (2017-03-13)
      Article
      Accés obert
      Stabbing a set S of n segments in the plane by a line is a well-known problem. In this paper we consider the variation where the stabbing object is a circle instead of a line. We show that the problem is tightly connected ...
    • Stabbing circles for some sets of Delaunay segments 

      Claverol Aguas, Mercè; Khramtcova, Elena; Papadopoulou, Evanthia; Saumell, Maria; Seara Ojea, Carlos (2016)
      Text en actes de congrés
      Accés obert
      Let S be a set of n segments in the plane such that, for every segment, its two endpoints are adjacent in the Delaunay triangulation of the set of endpoints of all segments in S. Our goal is to compute all the combinatorially ...
    • Stabbing segments with rectilinear objects 

      Claverol Aguas, Mercè; Garijo, Delia; Korman, Matias; Seara Ojea, Carlos; Silveira, Rodrigo Ignacio (2015-08-17)
      Capítol de llibre
      Accés restringit per política de l'editorial
      We consider stabbing regions for a set S of n line segments in the plane, that is, regions in the plane that contain exactly one endpoint of each segment of S. Concretely, we provide efficient algorithms for reporting all ...
    • Stabbing Segments with Rectilinear Objects 

      Claverol Aguas, Mercè; Seara Ojea, Carlos; Garijo, Delia; Korman, M.; Silveira, Rodrigo Ignacio (2013)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      Given a set of n line segments in the plane, we say that a region R of the plane is a stabber if R contains exactly one end point of each segment of the set. In this paper we provide efficient algorithms for determining ...
    • Stabbing segments with rectilinear objects 

      Claverol Aguas, Mercè; Garijo Royo, Delia; Korman, Matias; Seara Ojea, Carlos; Silveira, Rodrigo Ignacio (2017-09-15)
      Article
      Accés obert
      Given a set S of n line segments in the plane, we say that a region R¿R2 is a stabber for S if R contains exactly one endpoint of each segment of S. In this paper we provide optimal or near-optimal algorithms for ...
    • The [Theta]-operator and the low hierarchy 

      Castro Rabal, Jorge; Seara Ojea, Carlos (1992-07)
      Report de recerca
      Accés obert
      Long and Sheu in their paper [LS-91] introduced a refinement of the low hierarchy based on the [Theta]-levels of the polynomial time hierarchy which gives a deeper sight of the internal structure of NP. In this paper we ...
    • The alternating path problem revisited 

      Claverol Aguas, Mercè; Garijo, Delia; Hurtado Díaz, Fernando Alfredo; Lara Cuevas, María Dolores; Seara Ojea, Carlos (Universidad de Sevilla, 2013)
      Text en actes de congrés
      Accés obert
      It is well known that, given "n" red points and "n" blue points on acircle, it is not always possible to find a plane geometric. Hamiltonian alternating path. In this work we prove that if we relax the constraint on the ...
    • The Plogi and ACi-1 operators on the polynomial time hierarchy 

      Castro Rabal, Jorge; Seara Ojea, Carlos (1993-11)
      Report de recerca
      Accés obert
      In a previous paper ([CS-92]) we studied the agreement of operators P_{log^i} and AC^{i-1} acting on NP. In this article we extend this work to other classes of the polynomial time hierarchy. We show that on Sigma_k^p, ...
    • The Ø-operator and the low hierarchy 

      Castro Rabal, Jorge; Seara Ojea, Carlos (Universitat Politècnica de Catalunya. Departament de Llenguatges i Sistemes Informàtics, 1993)
      Text en actes de congrés
      Accés obert
      Long and Sheu in their paper [LS-91] introduced a refinement of the low hierarchy based on the Θ-levels of the polynomial time hierarchy which gives a deeper sight of the internal structure of N P. In this paper we show ...
    • Trees whose even-degree vertices induce a path are antimagic 

      Lozano Boixadors, Antoni; Mora Giné, Mercè; Seara Ojea, Carlos; Tey Carrera, Joaquín (2019-05-16)
      Report de recerca
      Accés obert
      An antimagic labeling of a connected graph G is a bijection from the set of edges E(G) to {1, 2, . . . , |E(G)|} such that all vertex sums are pairwise distinct, where the vertex sum at vertex v is the sum of the labels ...
    • Trees whose even-degree vertices induce a path are antimagic 

      Lozano Boixadors, Antoni; Mora Giné, Mercè; Seara Ojea, Carlos; Tey Carrera, Joaquín (2022-08)
      Article
      Accés obert
      An antimagic labeling of a connected graph G is a bijection from the set of edges E(G) to {1, 2, . . . , |E(G)|} such that all vertex sums are pairwise distinct, where the vertex sum at vertex v is the sum of the labels ...