On directed trades
نویسنده
چکیده
A (v, k, t) directed trade (or simply a (v, k, t)DT) of volume s consists of two disjoint collections Tl and each containing ordered k-tuples of distinct elements of a v-set called blocks, such that the number of blocks containing any t-tuple of V is the same in Tl as in T2 . Our study shows that the volume of a (v, k, t)DT is at least 2Lt/ 2J and that directed trades with minimum volume and minimum foundation exist. Also it is shown that for each s 2:: 2, there exists a (v, k, 2)DT and a (v, k,3)DT each of volume s, with one exception, that is, no (v,4, 3)DT of volume three exists.
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ورودعنوان ژورنال:
- Australasian J. Combinatorics
دوره 11 شماره
صفحات -
تاریخ انتشار 1995