Editing Neil Robertson (mathematician)

{{Short description|Canadian-American graph theorist (b.1938)}}
{{Infobox scientist
| name              = Neil Robertson
<!--  Commented out because image was deleted: | image = Neil Robertson (mathematician).jpg -->
| caption           = Photograph of Dr. Neil Robertson from<br>[[Ohio State University]]
| birth_date        = {{birth-date and age|November 30, 1938}}
| birth_place       =
| death_date        =
| death_place       = 
| nationality       =
| alma_mater        = [[University of Waterloo]],
| thesis_title      = Graphs Minimal under Girth, Valency and Connectivity Constraints
| thesis_year       = 1969
| doctoral_advisor  = [[William Tutte]]
| doctoral_students = {{plainlist|1=
*[[Paul A. Catlin]]
}}
| known_for         = [[Robertson–Seymour theorem]]
| footnotes         = 
| field             = [[Mathematician]]
| work_institution  = [[Ohio State University]]
| prizes            = [[Pólya Prize (SIAM)]] (2004, 2006)
| religion          =  
}}
'''George Neil Robertson''' (born November 30, 1938) is a mathematician working mainly in [[topological graph theory]], currently a distinguished professor emeritus at the [[Ohio State University]].<ref>[https://web.archive.org/web/20061207212411/http://www.math.ohio-state.edu/node/25682 Neil Robertson awarded the title of Distinguished Professor], David Goss, Ohio State, 2006-09-26.</ref><ref name="science"/>

==Education==
Robertson earned his B.Sc. from [[Brandon College]] in 1959 and his Ph.D. in 1969 at the [[University of Waterloo]] under his [[doctoral advisor]] [[William Tutte]].<ref>[https://www.brandonu.ca/sickle/YB1959.pdf The Sickle, Brandon College Year Book 1959] p.30</ref><ref>{{mathgenealogy|name=G. Neil (George) Robertson|id=11150}}</ref>

==Biography==
In 1969, Robertson joined the faculty of the Ohio State University, where he was promoted to Associate Professor in 1972 and Professor in 1984. He was a consultant with Bell Communications Research from 1984 to 1996. He has held visiting faculty positions in many institutions, most extensively at Princeton University from 1996 to 2001, and at Victoria University of Wellington, New Zealand, in 2002. He also holds an adjunct position at [[King Abdulaziz University]] in [[Saudi Arabia]].<ref name="science">{{citation|title=Saudi Universities offer cash in exchange for academic prestige |first=Yudhijit |last= Bhattacharjee |journal= [[Science (journal)|Science]] |date=9 December 2011 |pages=1344–1345 |doi= 10.1126/science.334.6061.1344 |volume=334 |issue=6061 |pmid=22158799|bibcode=2011Sci...334.1344B }}.</ref>

==Research==
Robertson is known for his work in [[graph theory]], and particularly for a long series of papers co-authored with [[Paul Seymour (mathematician)|Paul Seymour]] and published over a span of many years, in which they proved the [[Robertson–Seymour theorem]] (formerly called Wagner's Conjecture).<ref>{{Cite journal |last1=Robertson |first1=Neil |last2=Seymour |first2=P. D. |date=2004-11-01 |title=Graph Minors. XX. Wagner's conjecture |journal=Journal of Combinatorial Theory, Series B |series=Special Issue Dedicated to Professor W.T. Tutte |volume=92 |issue=2 |pages=325–357 |doi=10.1016/j.jctb.2004.08.001 |issn=0095-8956|doi-access=free }}</ref>  This states that families of graphs closed under the [[graph minor]] operation may be characterized by a [[finite set]] of [[forbidden minor]]s. As part of this work, Robertson and Seymour also proved the [[graph structure theorem]] describing the graphs in these families. <ref>{{Cite journal |last1=Robertson |first1=Neil |last2=Seymour |first2=P. D |date=2003-09-01 |title=Graph Minors. XVI. Excluding a non-planar graph |url=https://www.sciencedirect.com/science/article/pii/S009589560300042X |journal=Journal of Combinatorial Theory, Series B |volume=89 |issue=1 |pages=43–76 |doi=10.1016/S0095-8956(03)00042-X |issn=0095-8956}}</ref>

Additional major results in Robertson's research include the following:
*In 1964, Robertson discovered the [[Robertson graph]], the smallest possible 4-[[regular graph]] with [[girth (graph theory)|girth]] five.<ref>{{Cite journal |last=Robertson |first=Neil |date=1964 |title=The smallest graph of girth 5 and valency 4 |url=https://www.ams.org/bull/1964-70-06/S0002-9904-1964-11250-7/ |journal=Bulletin of the American Mathematical Society |language=en |volume=70 |issue=6 |pages=824–825 |doi=10.1090/S0002-9904-1964-11250-7 |issn=0273-0979|doi-access=free }}</ref>
*In 1993, with Seymour and [[Robin Thomas (mathematician)|Robin Thomas]], Robertson proved the <math>K_6
</math>-free case for which the [[Hadwiger conjecture (graph theory)|Hadwiger conjecture]] relating [[graph coloring]] to graph minors is known to be true. <ref>{{Cite journal |last1=Robertson |first1=Neil |last2=Seymour |first2=Paul |last3=Thomas |first3=Robin |date=1993-09-01 |title=Hadwiger's conjecture forK6-free graphs |url=https://doi.org/10.1007/BF01202354 |journal=Combinatorica |language=en |volume=13 |issue=3 |pages=279–361 |doi=10.1007/BF01202354 |issn=1439-6912}}</ref>
*In 1996, Robertson, Seymour, Thomas, and [[Daniel P. Sanders]] published a new proof of the [[four color theorem]],<ref>{{Cite journal |last1=Robertson |first1=Neil |last2=Sanders |first2=Daniel |last3=Seymour |first3=Paul |last4=Thomas |first4=Robin |date=1996 |title=A new proof of the four-colour theorem |url=https://www.ams.org/era/1996-02-01/S1079-6762-96-00003-0/ |journal=Electronic Research Announcements of the American Mathematical Society |language=en |volume=2 |issue=1 |pages=17–25 |doi=10.1090/S1079-6762-96-00003-0 |issn=1079-6762}}</ref> confirming the Appel–Haken proof which until then had been disputed. Their proof also leads to an efficient [[algorithm]] for finding 4-colorings of planar graphs.
*In 2006, Robertson, Seymour, Thomas, and [[Maria Chudnovsky]],  proved the long-conjectured [[strong perfect graph theorem]] characterizing the [[perfect graph]]s by forbidden [[induced subgraph]]s.<ref>{{Cite journal |last1=Chudnovsky |first1=Maria |last2=Robertson |first2=Neil |last3=Seymour |first3=Paul |last4=Thomas |first4=Robin |date=2006-07-01 |title=The strong perfect graph theorem |url=http://annals.math.princeton.edu/2006/164-1/p02 |journal=Annals of Mathematics |language=en |volume=164 |issue=1 |pages=51–229 |doi=10.4007/annals.2006.164.51 |issn=0003-486X|arxiv=math/0212070 }}</ref>

==Awards and honors==
Robertson has won the [[Fulkerson Prize]] three times, in 1994 for his work on the Hadwiger conjecture, in 2006 for the Robertson–Seymour theorem, and in 2009 for his participation in the proof of the strong perfect graph theorem.<ref>[https://www.ams.org/profession/prizes-awards/ams-prizes/fulkerson-prize Delbert Rey Fulkerson Prize], [[American Mathematical Society]], accessed 2012-01-03.</ref>

He also won the [[Pólya Prize (SIAM)]] in 2004, the OSU Distinguished Scholar Award in 1997, and the Waterloo Alumni Achievement Medal in 2002. In 2012 he became a fellow of the [[American Mathematical Society]].<ref>[https://www.ams.org/profession/fellows-list List of Fellows of the American Mathematical Society], retrieved 2013-07-07.</ref>

==See also==
* [[List of University of Waterloo people]]

==References==
{{reflist|40em}}
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==External links==
*[https://math.osu.edu/people/robertson.7 Neil Robertson's homepage] at [[Ohio State University]]
*[http://www.fmf.uni-lj.si/~mohar/Videos/Bled99_Robertson_DivXFull.avi Short conference video]. Neil Robertson - ''Some thoughts on [[Hadwiger conjecture (graph theory)|Hadwiger's Conjecture]]''. June 28, 1999. Video produced by [[Bojan Mohar]].

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[[Category:20th-century American mathematicians]]
[[Category:21st-century American mathematicians]]
[[Category:Graph theorists]]
[[Category:University of Waterloo alumni]]
[[Category:Living people]]
[[Category:1938 births]]
[[Category:Fellows of the American Mathematical Society]]
[[Category:Ohio State University faculty]]