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grammar, either "must have" or "has |
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Given a collection ''C'' of disjoint [[set theory|sets]], a '''transversal''' is a set containing exactly one member of each of them. In case that the original sets are not disjoint, there are several variations. One variation is that there is a [[bijection]] ''f'' from the transversal to ''C'' such that ''x'' is an element of ''f''(''x'') for each ''x'' in the transversal. Another is merely that the transversal must have non-empty intersection with each set in ''C''.
As an example of the first (disjoint-sets) meaning of ''transversal'',
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