An exposition of the compactness of $L(Q^{\mathrm{cf}})$

Abstract

We give an exposition of the compactness of $L(Q^{\mathrm{cf}})$, for any set $C$ of regular cardinals.

Several typos have been corrected. The proof of Theorem 4.3 has been slightly extended and corrected. The article will appear in The Bulletin of Symbolic Logic