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Mostrando ítems 1-10 de 29
Artículo
On Sedlacek's C-Graphs
(Societatea de Științe Matematice din România, 1993)
In this Note, we study some properties of Sedlacek's C-graphs (see [3], [4] and [5]). In particular, we give new methods to build infinite families of C-graphs starting by a C-graph, and we study the relationship between ...
Artículo
Triangle-Free Planar Graphs as Segments Intersection Graphs
(1999)
We prove that every triangle-free planar graph is the graph of intersection of a set of segments in the plane. Moreover, the segments can be chosen in only three directions (horizontal, vertical and oblique) and in such a ...
Artículo
The center of an infinite graph
(1996)
In this note we extend the notion of the center of a graph to infinite graphs. Thus, a vertex is in the center of the infinite graph G if it is in the center of an increasing family of finite subgraphs covering G. We give ...
Artículo
On p-minimal homological models of twisted tensor products of elementary complexes localised over a prime
(American Mathematical Society, 1999)
In this paper, working over Z(p) and using algebra perturbation results from [18], p-minimal homological models of twisted tensor products (TTPs) of Cartan’s elementary complexes are obtained. Moreover, making use of the ...
Artículo
3-filiform Lie algebras of dimension 8
(L'université Blaise Pascal, 1999)
We give, up to isomorphism and in dimension 8, all the 3-filiform Lie algebras (whose Goze’s invariant is (n - 3,1,1,1))..
Artículo
Geometric tree graphs of points in convex position
(1999)
Given a set P of points in the plane, the geometric tree graph of P is defined as the graph T(P) whose vertices are non-crossing spanning with straight edges trees of P, and where two trees T1 and T2 are adjacent if T2 = ...
Artículo
Embedding a graph in the grid of a surface with the minimum number of bends is NP-hard
(1997)
This paper is devoted to the study of graph embeddings in the grid of non-planar surfaces. We provide an adequate model for those embeddings and we study the complexity of minimizing the number of bends. In particular, we ...
Artículo
Artículo
An algorithm computing homotopy groups
(Elsevier, 1996)
An algorithm computing homotopy groups of a reduced simplicial set with effective homology is described, using the Whitehead tower method.
Artículo
Proper Homotopy Classification of Graphs
(London Mathematical Society, 1990)
This work presents a classification of the proper homotopy types of locally finite 1-dimensional CW-complexes.