## 1941

Because of this, I decided to take a look at Cardinal Algebras, a monograph by Alfred Tarski, né Alfred Teitelbaum, published by Oxford University Press in 1949.

Here is the closing paragraph of the Preface:

It would be impossible for me to conclude this introduction without mentioning one more namethat of Adolf Lindenbaum, a former student and colleague of mine at the University of Warsaw. My close friend and collaborator for many years, he took a very active part in the earlier stages of the research which resulted in the present work, and the few references to his contribution that will be found in the book can hardly convey an adequate idea of the extent of my indebtedness. The wave of organized totalitarian barbarism engulfed this man of unusual intelligence and great talentas it did millions of others.${}^4$

${}^4$ Adolf Lindenbaum was killed by the Gestapo in 1941.

1. I find Lindenabum’s name completely missing from the set theoretical terminology. This is why I usually refer to $\aleph^*(X)$ as “Lindenbaum number of $X$” (after all, it was Lindenbaum who proved the analogue of Hartogs theorem for $\leq^\ast$).