Lenhard Ng

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Lenhard L Ng
Born 1976
Residence Berkeley, California
Nationality United States[1]
Fields Mathematics
Institutions Duke University
Mathematical Sciences Research Institute
Alma mater Massachusetts Institute of Technology
Harvard University
Doctoral advisor Tomasz Mrowka
Known for Differential Geometry
Gauge Theory
Legendrian Submanifolds

Lenhard Ng (born 1976, United States) is an American mathematician, working primarily on symplectic geometry. Ng is an associate professor of mathematics at Duke University.[2]

Personal life[edit]

Lenhard Ng is an American of Chinese descent. His father, Jack Ng, is a professor of Physics at University of North Carolina Chapel Hill. He earned his B.A. (Summa Cum Laude) in Mathematics and Physics at Harvard University and his Ph.D. in Mathematics at the Massachusetts Institute of Technology in 2001. He is married to Astrid Giugni.

Child prodigy[edit]

Ng was a child prodigy[3] who was once thought to be the "smartest kid in America". At age 10, he earned a perfect score of 800 on the math portion of the SAT-I. He is one of the youngest children to have achieved this feat. At the age of 11, he earned a perfect score on the College Board Test of Standard Written English. He earned a perfect score on the American High School Mathematics Examination in all 4 years of high school. He attended the Johns Hopkins Center for Talented Youth and was one of the gifted children included in the Study of Mathematically Precocious Youth longitudinal cohort. He was estimated to be top one in approximately one million of his age-mates.

At the age of 12, he began taking courses (on a part-time basis) at the University of North Carolina, Chapel Hill. He was not yet 13 when he won the Written Round of the MATHCOUNTS competition. At the age of 14, he participated in the International Mathematical Olympiad and earned a Silver medal.[4] He participated in this competition for the next two years and earned Gold medals. He entered college (Harvard University) full-time at the age of 16 and majored in Mathematics and Physics, graduating summa cum laude in three years. He competed in the William Lowell Putnam Mathematical Competition while at Harvard University and was a three-time fellow, one of only 18[5] people to have achieved this feat since 1938. The first time he became a Putnam Fellow was at the age of 16, making him one of only 6 people (the 5 others being Arthur Rubin, Noam Elkies, Don Zagier, David Ash and John Tillinghast) in the history of the competition to have achieved this feat.[6]

Mathematical work[edit]

Ng works in contact and symplectic geometry. His Ph.D. thesis and several other papers concern Legendrian knots, and his best-known work applies symplectic field theory to derive invariants of (topological) knots. More precisely, the conormal bundle of a knot embedded in the three-sphere is a Legendrian torus inside the three-sphere's unit cosphere bundle (a contact five-manifold). Relative contact homology produces symplectic invariants of this pair, which give topological invariants of the knot. Ng computed the linearized contact homology in this case, providing an entirely combinatorial model for it which is a powerful knot invariant.


Ng, Lenhard. Knot and braid invariants from contact homology I. Geom. Topol. 9 (2005), 247–297. Ng, Lenhard. Knot and braid invariants from contact homology II. Geom. Topol. 9 (2005), 1603–1637.

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