Extreme point axioms for closure spaces

نویسنده

  • Kazutoshi Ando
چکیده

A pair (X, ) of a finite set X and a closure operator : 2X → 2X is called a closure space. The class of closure spaces includes matroids as well as antimatroids. Associated with a closure space (X, ), the extreme point operator ex: 2X → 2X is defined as ex(A) = {p|p ∈ A,p / ∈ (A − {p})}. We give characterizations of extreme point operators of closure spaces, matroids and antimatroids, respectively. © 2006 Elsevier B.V. All rights reserved.

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عنوان ژورنال:
  • Discrete Mathematics

دوره 306  شماره 

صفحات  -

تاریخ انتشار 2006