Eliyahu Rips

Eliyahu Rips
Born	1948 (age 63–64) Latvia
Nationality	Israeli
Fields	Mathematics
Institutions	Hebrew University
Alma mater	University of Latvia Hebrew University
Doctoral advisor	Shimshon Amitsur
Doctoral students	Lev Birbrair Zlil Sela
Known for	Rips machine Vietoris–Rips complex Torah Code

Eliyahu Rips, also Ilya Rips (Hebrew: אליהו ריפס‎; Russian: Илья Рипс; born 1948) is a Latvian-born Israeli mathematician known for his research in geometric group theory. He became known to the general public following his coauthoring a paper on what is popularly known as Bible code, the supposed coded messaging in the Hebrew text of the Torah.

Biography

Rips grew up in Latvia (then part of Soviet Union). He was the first high school student from Latvia to participate in the International Mathematical Olympiad. On 9 April 1969, Rips, then a graduate student at the University of Latvia, attempted self-immolation in a protest against the Soviet invasion of Czechoslovakia. After that, he was incarcerated by the Soviet government for two years but, under pressure from Western mathematicians, was allowed to emigrate to Israel in 1972.

After recovering from his wounds and finishing his Ph.D., Rips joined the Department of Mathematics at the Hebrew University of Jerusalem. In 1975, he completed his PhD in mathematics at Hebrew University. His topic was the dimensional sub-group problem. His dissertation was recognized as being of international interest and he was awarded with the prestigious Aharon Karzir Prize. In 1979, Rips received the Erdős Prize from the Israel Mathematical Society, and was a sectional speaker at the International Congress of Mathematicians in 1994.

Since completing his PhD, he has been on the faculty of the Department of Mathematics, at Hebrew University where he holds the position of Professor. His current research interests concentrate on geometric and combinatorial methods in infinite group theory. This includes small cancellation theory and its generalizations, (Gromov) hyperbolic group theory, Bass-Serre theory and the actions of groups on R-trees.

Rips' (mostly unpublished) work on group actions on $\mathbb R$-trees has been widely influential. The Rips machine, in the hands of Rips and his student Zlil Sela, has proven to be effective in obtaining classification results such as a solution to the isomorphism problem for hyperbolic groups.

The Bible Code controversy

In the late seventies, Rips began looking with the help of a computer for codes in the Torah. In 1994, Rips, together with Doron Witztum and Yoav Rosenberg, published a seminal article in the journal Statistical Science, "Equidistant Letter Sequences in the Book of Genesis", which claimed the discovery of encoded messages in the Hebrew text of Genesis. This, in turn, was the inspiration for the 1997 book The Bible Code by journalist Michael Drosnin. While Rips originally claimed that he agreed with Drosnin's findings, he later distanced himself from his interpretations. Since Drosnin's book, Bible codes have been a subject of controversy, with the claims being criticized by Brendan McKay and others.

Selected papers

• Rips, E.. "Group actions on R-trees". preprint. 
• Rips, E. (1982). "Subgroups of small cancellation groups". Bull. London Math. Soc. 14 (1): 45–47. 
• Rips, E.; Sela, Z. (1994). "Structure and rigidity in hyperbolic groups. I". Geom. Funct. Anal. 4 (3): 337–371. 
• Rips, E.; Sela, Z. (1995). "Canonical representatives and equations in hyperbolic groups". Invent. Math. 120 (3): 489–512. 
• Rips, E.; Sela, Z. (1997). "Cyclic splittings of finitely presented groups and the canonical JSJ decomposition". Ann. of Math. 2 146 (1): 53–109. 
• Sapir, Mark V.; Birget, Jean-Camille; Rips, Eliyahu (2002). "Isoperimetric and isodiametric functions of groups". Ann. of Math. 2 156 (2): 345–466. 
• Birget, J.-C.; Ol'shanskii, A. Yu.; Rips, E.; Sapir, M. V. (2002). "Isoperimetric functions of groups and computational complexity of the word problem". Ann. of Math. 2 156 (2): 467–518. 

References

• Grūtups, A. (2009). Observators. Rīga: Atēna.

External links

• The Bible Code, transcript of a story which aired on BBC Two, Thursday 20 November 2003, featuring comments by Drosnin, Rips, and Brendan McKay.
• Eliyahu Rips at the Mathematics Genealogy Project.
• Eliyahu Rips's results at the International Mathematical Olympiad