摘 要: | Let X be a v-set. Let A be a family of some k-subsets (called bl-ocks) of X. The pair (X, A) is called a balanced incomplete blockdesign, denoted by (u, k, λ) -BIBD, if any two distinct elements ofX are contained in exactly λ blocks of A. Some simple computationshows, for any given integers v, k and λ, a (v, k, λ)-BIBD existsonly if
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