Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-27T02:32:07.335Z Has data issue: false hasContentIssue false

A CRITERION FOR THE EXISTENCE OF TRANSVERSALS OF SET SYSTEMS

Published online by Cambridge University Press:  01 December 1997

JERZY WOJCIECHOWSKI
Affiliation:
Department of Mathematics, West Virginia University, P.O. Box 6310, Morgantown, West Virginia 26506-6310, USA. E-mail: [email protected]
Get access

Abstract

Nash-Williams [6] formulated a condition that is necessary and sufficient for a countable family [Ascr ]=(Ai)iI of sets to have a transversal. In [7] he proved that his criterion applies also when we allow the set I to be arbitrary and require only that [xcap ]iJAi=[emptyv ] for any uncountable JI. In this paper, we formulate another criterion of a similar nature, and prove that it is equivalent to the criterion of Nash-Williams for any family [ufr ]. We also present a self-contained proof that if [xcap ]iJAi=[emptyv ] for any uncountable JI, then our condition is necessary and sufficient for the family [ufr ] to have a transversal.

Type
Notes and Papers
Copyright
The London Mathematical Society 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)