Robert Tarjan

Infobox Scientist
name = Robert Endre Tarjan


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birth_date = Birth date and age|1948|4|30|mf=y
birth_place = Pomona, California
death_date =
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field = Computer Science
work_institution = Princeton University
Hewlett-Packard
alma_mater = Caltech, Stanford
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known_for = Tarjan's off-line least common ancestors algorithm
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prizes = Turing Award
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Robert Endre Tarjan (born April 30, 1948 in Pomona, California) is a renowned American computer scientist. He is the discoverer of several important graph algorithms, including Tarjan's off-line least common ancestors algorithm, and co-inventor of both splay trees and Fibonacci heaps.

Education

Robert Tarjan's father was a child psychiatrist specializing in mental retardation, and ran a state hospital.cite book
last = Shasha
first = Dennis Elliott
coauthors = Lazere, Cathy A.
title = Out of Their Minds: The Lives and Discoveries of 15 Great Computer
pubilsher = Copernicus/Springer
origyear = 1995
year = 1998
isbn = 978-0387979922
oclc = 32240355
chapter = Robert E. Tarjan: In Search of Good Structure
page = 102-119] As a kid, Tarjan read a lot of science fiction, and wanted to be an astronomer. He became interested in mathematics after reading Martin Gardner's mathematical games column in Scientific American. He became seriously interested in math in the eighth grade, thanks to a "very stimulating" teacher.

While he was in high school, Tarjan got a job, where he worked IBM card punch collators. He first worked with real computers at a summer science program in 1964.

Tarjan obtained a Bachelor's degree in mathematics from the California Institute of Technology in 1969. At Stanford University, he received his Master's degree in computer science in 1971 and a Ph.D. in computer science (with a minor in mathematics) in 1972. At Stanford, he was supervised by Robert Floyd and Donald Knuth, both highly prominent computer scientists. His Ph.D. dissertation was "An Efficient Planarity Algorithm", and his advisor was eminent computer scientist Robert Floyd. [cite web
url = http://genealogy.math.ndsu.nodak.edu/id.php?id=53460
title = Robert Endre Tarjan
publisher = Mathematics Genealogy Project
accessdate = 2008-01-09] Tarjan selected computer science as his area of interest, because he believed that CS was a way of doing mathematics that could have a practical impact.cite web
url = http://www.hpl.hp.com/news/2004/oct_dec/tarjan.html
title = Robert Endre Tarjan: The art of the algorithm (interview)
year = 2004
month = September
publisher = Hewlett-Packard
accessdate = 2008-01-09]

Computer science career

Tarjan has been teaching at Princeton University since 1985. He has also held academic positions at Cornell University (1972-73), University of California, Berkeley (1973-1975), Stanford University (1974-1980), and New York University (1981-1985). He has also been a fellow of the NEC Research Institute (1989-1997), a Visiting Scientist at the Massachusetts Institute of Technology (1996).

Tarjan has vast industrial experience: he has worked at AT&T Bell Labs (1980-1989), InterTrust Technologies (1997-2001), Compaq (2002) and Hewlett Packard (2006-present). He has served on several ACM and IEEE committees, and has also been editor of several reputed journals.

Algorithms and data structures

Tarjan has designed many efficient algorithms and data structures for solving problems in a wide variety of application areas. He has published more than 228 refereed journal articles and book chapters.

Tarjan is known for his pioneering work on graph theory algorithms and data structures. Some of his well-known algorithms include the "Tarjan's off-line least common ancestors algorithm" (used to compute the lowest common ancestors for pairs of nodes in a tree), and the Tarjan's strongly connected components algorithm (used to the strongly connected components of a graph).The Hopcroft-Tarjan planarity algorithm was the first linear-time algorithm for planarity-testing. [cite book
last = Kocay
first = William
coauthors = Kreher, Donald L
title = Graphs, algorithms, and optimization
pubilsher = Chapman & Hall/CRC
location = Boca Raton
year = 2005
isbn = 978-1584883968
oclc = 56319851
chapter = Planar Graphs
page = 312]

Tarjan has also developed important data structures such as the Fibonacci heap (a heap data structure consisting of a forest of trees), and the splay tree (a self-adjusting binary search tree; co-invented by Tarjan and Daniel Sleator).

Tarjan is currently the James S. McDonnell Distinguished University Professor of Computer Science at Princeton University, and also works for Hewlett-Packard.cite web
url = http://www.hpl.hp.com/about/honors/HPfellows/tarjan.html
title = HP Fellows: Robert Endre Tarjan
publisher = Hewlett-Packard
accessdate = 2008-01-09]

Awards

Tarjan received the Turing Award jointly with John Hopcroft in 1986. The citation for the award states that it was:

:For fundamental achievements in the design and analysis of algorithms and data structures.

Tarjan was also elected an ACM Fellow in 1994. The citation for this award [http://www.acm.org/awards/fellows_citations_n-z/tarjan.html] states:

:For seminal advances in the design and analysis of data structures and algorithms.

Some of the other awards for Tarjan include:
* Nevanlinna Prize in Information Science (1983) - first recipient
* National Academy of Sciences Award for Initiatives in Research (1984)
* Paris Kanellakis Award in Theory and Practice, ACM (1999)
* Blaise Pascal Medal in Mathematics and Computer Science, European Academy of Sciences (2004)

References

Bibliography

* cite book
last = Tarjan
first = Robert E.
title = Data structures and network algorithms
pubilsher = Society for Industrial and Applied Mathematics
location = Philadelphia
year = 1983
isbn = 978-0898711875
oclc = 10120539
* cite book
last = Tarjan
first = Robert E.
coauthors = Polya, George; Woods, Donald R
title = Notes on introductory combinatorics
pubilsher = Birkhauser
location = Boston
year = 1983
isbn = 978-0817631703
oclc = 10018128
* [http://worldcat.org/search?q=au%3ARobert+E+Tarjan OCLC entries] for Robert E Tarjan
* [http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/t/Tarjan:Robert_Endre.html DBLP entry] for Robert Endre Tarjan

External links

* [http://dblp.uni-trier.de/db/indices/a-tree/t/Tarjan:Robert_Endre.html DBLP: Robert Endre Tarjan]
* [http://www.cs.princeton.edu/~ret/ Robert Tarjan's home page at Princeton] .
* [http://genealogy.math.ndsu.nodak.edu/id.php?id=53460 Mathematics Genealogy Project entry] for Robert Endre Tarjan.

Persondata
NAME= Tarjan, Robert Endre
ALTERNATIVE NAMES=
SHORT DESCRIPTION= Computer scientist
DATE OF BIRTH= April 30, 1948
PLACE OF BIRTH= Pomona, California
DATE OF DEATH=
PLACE OF DEATH=