J Austral Math Soc Ser A 56 pp117--124, 1994.
(Received 30 July 1991)
In Zermelo-Fraenkel set theory weakened to permit the existence of atoms and without the axiom of choice we investigate the deductive strength of five statements which make assertions about the cardinality of the union of a well-ordered collection of sets. All five of the statements considered are consequences of the axiom of choice.
1991 AMS Subject Classification: 03E35, 03E25, 04A25
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