Completely separating systems of k-sets

نویسندگان

  • Colin Ramsay
  • Ian T. Roberts
  • Frank Ruskey
چکیده

Dickson On a problem concerning separating systems of a nite set, Journal of Combinatorial Theory, 7 (1969), 191{196.] introduced the notion of a completely separating set system. We study such systems with the additional constraint that each set in the system has the same size. Let T denote an n-set. We say that a subset S of T separates i from j if i 2 S and j 6 2 S. A collection of k-sets C is called a (n; k)-separator if, for each ordered pair (i; j) 2 T T with i 6 = j, there is a set S 2 C which separates i from j. Let R(n; k) denote the size of a smallest (n; k)-separator. For n k(k-1) we show that R(n; k) = d2n=ke. We also show that R(2 m ; 2 m-1) 2m and demonstrate various recursive relationships that are used to determine the exact values of R(n; k) for k 5.

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عنوان ژورنال:
  • Discrete Mathematics

دوره 183  شماره 

صفحات  -

تاریخ انتشار 1998