**Authors**: Thomas Jech and Saharon Shelah

**Title:** *Possible pcf algebras*

J. Symb. Logic 61 (1996)

**Abstract:** We prove the existence of a structure on countable ordinals
that is relevant to the singular cardinals problem.

**Author**: Thomas Jech

**Title:** *Singular cardinals and the pcf theory*

Bull. Symb. Logic 1 (1995)

**Abstract:** An expository article on the singular cardinals problem.

**Author**: Thomas Jech

**Title:** *A variation on a theorem of Galvin and Hajnal*

Bull. London Math. Soc. 25 (1993)

**Abstract:** Using methods of Shelah's pcf theory, we prove an upper
bound on the length of cofinal scales
in reduced products, using the Galvin-Hajnal norm.

**Author**: Thomas Jech

**Title:** *Singular cardinal problem: Shelah's theorem on
2 to aleph_omega*

Bull. London Math. Soc. 24 (1992)

**Abstract:** This is an expository paper giving a complete proof of a
celebrated theorem of Saharon Shelah.

**Authors**: Thomas Jech and Saharon Shelah

**Title:** *On a conjecture of Tarski on products of cardinals *

Proceedings AMS 112 (1991)

**Abstract:** We look at an old conjecture of A. Tarski on
cardinal arithmetic and show that if a counterexample exists,
then there exists one of length omega_1 + omega.