No CrossRef data available.
Published online by Cambridge University Press: 12 March 2014
Let be the class of structures 〈λ, <, A〉, where A ⊆ λ is disjoint from a club, and let
be the class of structures 〈λ, <, A), where A ⊆ λ contains a club. We prove that if λ = λ<κ is regular, then no sentence of Lλ + κ separates
and
On the other hand, we prove that if λ = μ+ , μ = μ<μ, and a forcing axiom holds (and
if μ = ℵ0), then there is a sentence of Lλλ which separates
and
.