# Lenhard Lee Ng

- Professor of Mathematics
- Eads Family Professor

**External address:**216 Physics Bldg, 120 Science Drive, Durham, NC 27708

**Internal office address:**Box 90320, Durham, NC 27708-0320

**Phone:**(919) 660-6972

**Office Hours:**

Spring 2018:

- Mondays 2:00-3:00
- Thursdays 11:00-12:00

and by appointment.

### Research Areas and Keywords

##### Geometry: Differential & Algebraic

##### Mathematical Physics

##### Topology

My research mainly focuses on symplectic topology and low-dimensional topology. I am interested in studying structures in symplectic and contact geometry (Weinstein manifolds, contact manifolds, Legendrian and transverse knots), especially through holomorphic-curve techniques. One particular interest is extracting topological information about knots through cotangent bundles, and exploring relations to topological string theory. I have also worked in Heegaard Floer theory, quantum topology, and sheaf theory, especially as they relate to Legendrian and transverse knots.

Ng, L, and Rutherford, D. "Satellites of Legendrian knots and representations of the Chekanov-Eliashberg Algebra." *Algebraic and Geometric Topology* 13.5 (2013): 3047-3097.
Full Text

Ekholm, T, Etnyre, J, Ng, L, and Sullivan, M. "Filtrations on the knot contact homology of transverse knots." *Mathematische Annalen* (2012): 1-31.
Full Text

Ng, L. "On arc index and maximal Thurston-Bennequin number." *Journal of Knot Theory and Its Ramifications* 21.4 (2012).

Ng, L. "Combinatorial knot contact homology and transverse knots." *Advances in Mathematics* 227.6 (2011): 2189-2219.
Full Text

Chongchitmate, W, and Ng, L. "An atlas of Legendrian knots (Accepted)." *Experimental Mathematics* (2011). (Academic Article)

Etnyre, J, Ng, L, and Vertesi, V. "Legendrian and transverse twist knots (Accepted)." *Journal of the European Mathematical Society* (2011). (Academic Article)

Khandhawit, T, and Ng, L. "A family of transversely nonsimple knots." *Algebraic and Geometric Topology* 10.1 (2010): 293-314.
Full Text

Ng, L. "Rational symplectic field theory for Legendrian knots." *Inventiones Mathematicae* 182.3 (2010): 451-512.
Full Text

Ng, L. "Framed knot contact homology." *Duke Mathematical Journal* 141.2 (2008): 365-406.
Full Text

Lenhard, NG. "A skein approach to bennequin-type inequalities." *International Mathematics Research Notices* 2008.1 (2008).
Full Text