Displaying similar documents to “On contractible fans”

Digraphs contractible onto * K 3

Stefan Janaqi, François Lescure, M. Maamoun, Henry Meyniel (1998)

Mathematica Bohemica

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We show that any digraph on n ≥ 3 vertices and with not less than 3 n - 3 arcs is contractible onto * K 3 .

The Freudenthal space for approximate systems of compacta and some applications.

Ivan Loncar (1995)

Publicacions Matemàtiques

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In this paper we define a space σ() for approximate systems of compact spaces. The construction is due to H. Freudenthal for usual inverse sequences [4, p. 153–156]. We establish the following properties of this space: (1) The space σ() is a paracompact space, (2) Moreover, if is an approximate sequence of compact (metric) spaces, then σ() is a compact (metric) space (Lemma 2.4). We give the following applications of the space σ(): (3) If is an approximate system of continua, then...

Symmetrized and continuous generalization of transversals

Martin Kochol (1996)

Mathematica Bohemica

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The theorem of Edmonds and Fulkerson states that the partial transversals of a finite family of sets form a matroid. The aim of this paper is to present a symmetrized and continuous generalization of this theorem.