8 research outputs found

    Score lists in multipartite hypertournaments

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    Given non-negative integers nin_{i} and αi\alpha_{i} with 0≤αi≤ni0 \leq \alpha_{i} \leq n_i (i=1,2,...,k)(i=1,2,...,k), an [α1,α2,...,αk][\alpha_{1},\alpha_{2},...,\alpha_{k}]-kk-partite hypertournament on ∑1kni\sum_{1}^{k}n_{i} vertices is a (k+1)(k+1)-tuple (U1,U2,...,Uk,E)(U_{1},U_{2},...,U_{k},E), where UiU_{i} are kk vertex sets with ∣Ui∣=ni|U_{i}|=n_{i}, and EE is a set of ∑1kαi\sum_{1}^{k}\alpha_{i}-tuples of vertices, called arcs, with exactly αi\alpha_{i} vertices from UiU_{i}, such that any ∑1kαi\sum_{1}^{k}\alpha_{i} subset ∪1kUi′\cup_{1}^{k}U_{i}^{\prime} of ∪1kUi\cup_{1}^{k}U_{i}, EE contains exactly one of the (∑1kαi)!(\sum_{1}^{k} \alpha_{i})! ∑1kαi\sum_{1}^{k}\alpha_{i}-tuples whose entries belong to ∪1kUi′\cup_{1}^{k}U_{i}^{\prime}. We obtain necessary and sufficient conditions for kk lists of non-negative integers in non-decreasing order to be the losing score lists and to be the score lists of some kk-partite hypertournament

    On Scores, Losing Scores and Total Scores in Hypertournaments

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    A kk-hypertournament is a complete kk-hypergraph with each kk-edge endowed with an orientation, that is, a linear arrangement of the vertices contained in the edge. In a kk-hypertournament, the score sis_{i} (losing score rir_{i}) of a vertex viv_{i} is the number of arcs containing viv_{i} in which viv_{i} is not the last element (in which viv_{i} is the last element). The total score of viv_{i} is defined as ti=si−rit_{i}=s_{i}-r_{i}. In this paper we obtain stronger inequalities for the quantities ∑i∈Iri\sum_{i\in I}r_{i}, ∑i∈Isi\sum_{i\in I}s_{i} and ∑i∈Iti\sum_{i\in I}t_{i}, where I⊆{1,2,…,n}I\subseteq \{ 1,2,\ldots,n\}. Furthermore, we discuss the case of equality for these inequalities. We also characterize total score sequences of strong kk-hypertournaments

    Acta Universitatis Sapientiae - Informatica 2010

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    Acta Universitatis Sapientiae - Informatica 2018

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    Deciding football sequences

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    An open problem posed by the first author is the complexity to decide whether a sequence of nonnegative integer numbers can be the final score of a football tournament. In this paper we propose polynomial time approximate and exponential time exact algorithms which solve the problem
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