No CrossRef data available.
Published online by Cambridge University Press: 12 March 2014
Two cardinals are said to be indistinguishable if there is no sentence of second order logic which discriminates between them. This notion, which is defined precisely below, is closely related to that of characterizable cardinals, introduced and studied by Garland in [3]. In this paper we give an algebraic criterion for two cardinals to be indistinguishable. As a consequence we obtain a straightforward proof of an interesting theorem about characterizable cardinals due to Zykov [6].
Most of the results given here were presented at the British Mathematical Colloquium, Birmingham, March 1969.