Valentin Poénaru
Encyclopedia
Valentin Alexandre Poénaru (born 1932) is a Professor of Mathematics at Université de Paris-Sud. He specializes in low-dimensional topology
.
Born in Romania
, he did his undergraduate studies at the University of Bucharest
. In 1962, he was an invited speaker at the International Congress of Mathematicians
in Stockholm
, Sweden
. While at the congress, Poénaru defected
, subsequently leaving for France. He defended his Thèse d'État at the University of Paris
on March 23, 1963. His dissertation topic was Sur les variétés tridimensionnelles ayant le type d'homotopie de la sphère S3, and was written under the supervision of Charles Ehresmann
. After that, he went to the United States
, spending four years at Harvard University
and Princeton University
. In 1967, he returned to France.
Poénaru has worked for several decades on a proof of the Poincaré conjecture
, making a number of related breakthroughs. His first attempt at proving the conjecture dates from 1957. He has described his general approach over the years in different papers and conferences. On December 19, 2006, he posted a preprint to the arXiv
, claiming to have finally completed the details of his approach and proven the conjecture.
Low-dimensional topology
In mathematics, low-dimensional topology is the branch of topology that studies manifolds of four or fewer dimensions. Representative topics are the structure theory of 3-manifolds and 4-manifolds, knot theory, and braid groups. It can be regarded as a part of geometric topology.A number of...
.
Born in Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
, he did his undergraduate studies at the University of Bucharest
University of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...
. In 1962, he was an invited speaker at the International Congress of Mathematicians
International Congress of Mathematicians
The International Congress of Mathematicians is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union ....
in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. While at the congress, Poénaru defected
Defection
In politics, a defector is a person who gives up allegiance to one state or political entity in exchange for allegiance to another. More broadly, it involves abandoning a person, cause or doctrine to whom or to which one is bound by some tie, as of allegiance or duty.This term is also applied,...
, subsequently leaving for France. He defended his Thèse d'État at the University of Paris
University of Paris
The University of Paris was a university located in Paris, France and one of the earliest to be established in Europe. It was founded in the mid 12th century, and officially recognized as a university probably between 1160 and 1250...
on March 23, 1963. His dissertation topic was Sur les variétés tridimensionnelles ayant le type d'homotopie de la sphère S3, and was written under the supervision of Charles Ehresmann
Charles Ehresmann
Charles Ehresmann was a French mathematician who worked on differential topology and category theory. He is known for work on the topology of Lie groups, the jet concept , and his seminar on category theory.He attended the École Normale Supérieure in Paris before performing one year of military...
. After that, he went to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, spending four years at Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
and Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
. In 1967, he returned to France.
Poénaru has worked for several decades on a proof of the Poincaré conjecture
Poincaré conjecture
In mathematics, the Poincaré conjecture is a theorem about the characterization of the three-dimensional sphere , which is the hypersphere that bounds the unit ball in four-dimensional space...
, making a number of related breakthroughs. His first attempt at proving the conjecture dates from 1957. He has described his general approach over the years in different papers and conferences. On December 19, 2006, he posted a preprint to the arXiv
ArXiv
The arXiv |Chi]], χ) is an archive for electronic preprints of scientific papers in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance which can be accessed online. In many fields of mathematics and physics, almost all...
, claiming to have finally completed the details of his approach and proven the conjecture.
External links
- Terza e quarta dimensione: un mistero da svelare, interview by Marinella Daidone from Università degli Studi di TrentoUniversity of TrentoThe University of Trento is an Italian university located in the cities of Trento and Rovereto. It has been able to achieve considerable results in didactics, research and international relations, as shown by Censis University Guide and by the Italian Ministry of...
, Unitn, no. 52, April, 2003.