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Opinion 103:
Israel Moiseevich Gelfand (Sept. 2, 1913-Oct. 5, 2009)

## By Doron Zeilberger

Written: 2:00 pm , Oct. 6, 2009

At these very moments, one of my great heroes, Israel Gelfand, is getting buried at the Floral Park
Cemetery at Deans, NJ, and out of repsect to the family's wishes to keep it private, I decided
not to attend it. Instead I am writing these lines.

Five years ago I explained
why Israel Gelfand didn't "die" in Erdös' sense. While it seems that he "died" yesterday,
in the vernacular sense of the word, he sure didn't. His mathematical heritage
will stay with us for ever!

The prior probability that anyone would be a great mathematician is
very very small. The probability that anyone would be a great
mathematician *and* live so long, is smaller still. Let me
take this opportunity to thank two people, in particular, who
contibuted to the longevity of Israel. One is Tanya, his beloved
wife, who took care both of his physical and spiritual
(non-mathematical) needs, and especially turned him into a strict
Vegan, like herself. I am sure that this added many years to his
life. The other is his close collaborator, and most devoted disciple,
Volodia Retakh,
who, together with another devoted disciple, Robert Wilson, and
Gelfand's son Sergei, collaborated on many different and fascinating projects.
This collaboration kept him alive mathematically much longer than
anyone else I know of, and, most probably, also contributed to his
longevity.

True or False?:
the greatest mathematician of the second half of the 20th century died yesterday.

False! It is bad English to use the word "greatest" on sets whose cardinality is ≤ 2 . Israel Gelfand
was the **only** surviving mathematician in the second half of the 20th century, since both
Hilbert and Poincaré were already dead. There are lots of great algebraists, analysts, combinatorialists, number-theorists, topologists,
etc. alive to day, but until the day before yesterday,
the set of living *mathematicians* was a singleton, and
yesterday it became the empty set.

ת ה י ה נ ש מ ת ו צ ר ו ר ה ב צ ר ו ר ה ח י י ם

Added Oct. 12, 2009: read
Tatiana V. Gelfand's comment

Added Jan. 19, 2010: read
Volodia Retakh's moving words

Opinions of Doron Zeilberger
Added Feb. 14, 2011:
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