A General Criterion for the Existence of Transversals
نویسنده
چکیده
We present a necessary and sufficient condition for a family of sets to possess a transversal. Its form follows that of P. Hall's theorem: a family has a transversal if and only if it does not contain one of a set of 'forbidden' substructures.
منابع مشابه
Another Form of a Criterion for the Existence of Transversals
In [2] we proved a necessary and sufficient condition for a family of sets to possess a transversal. We now prove a slightly more concrete version of this result, using the function q of [4].
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