Shelah's main interest lies in mathematical logic, in particular in model theory and set theory.

Shelah is one of the most prolific contemporary mathematicians. As of 2003, he has (together with about 190 coauthors) published more than 750 mathematical papers.

*write something about his work: classification theory/stability
proper forcing.
pcf theory.
Whitehead problem. van der Waerden numbers.
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