# William L. Pardon

- Professor of Mathematics

**External address:**219 Physics Bldg, Durham, NC 27708

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

**Phone:**(919) 660-2838

**Office Hours:**

T, 1:30-3:00

W, 12:00-2:30

### Research Areas and Keywords

##### Algebra & Combinatorics

##### Analysis

##### Geometry: Differential & Algebraic

##### Number Theory

##### Topology

In [1] an old question of de Rham about the topological classification of rotations of Euclidean space was largely

answered in the affirmative.

Methods of algebraic K-theory were used to study quadratic forms defined over an affine k-algebra in [2] and [4],

and to relate their properties to geometric properties of the variety underlying the k-algebra ([3]).

More recently Professor Pardon has studied the algebraic topology and differential geometry of singular spaces

([5], [6], [10]). In particular [5] and [6] examine how the singularities of a space limit the existence of characteristic

classes; on the other hand, in the case of arbitrary Hermitian locally symmetric spaces, [10] shows how

characteristic classes on the smooth locus may be extended canonically over the singularities, even when the

tangent bundle does not so extend.

Paper [7] looks at the arithmetic genus, in the sense of L2-cohomology, of singular algebraic surfaces. In [8]

Professor Pardon and Professor Stern verify a conjecture of MacPherson and settle the questions partially

answered in [7]; in [9] they give an analytic description of the Hodge structure on the intersection homology of a

variety with isolated singularities.

Quadratic Forms on Schemes awarded by National Science Foundation (Principal Investigator). 2000 to 2005

(95-0296) Geometry & Topology of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1995 to 1998

(96-0506) Geometry & Topology of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1995 to 1998

(97-0879) Geometry and Topology of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1995 to 1998

(94-0810) Mathematical Sciences: Topology and Geometry of Algebraic Varieties awarded by National Science Foundation (Principal Investigator). 1992 to 1996

(92-0265) Mathematical Sciences: Topology and Geometry of Algebraic Varieties awarded by National Science Foundation (Principal Investigator). 1992 to 1995

(94-0057) Mathematical Sciences: Topology and Geometry of Algebraic Varieties awarded by National Science Foundation (Principal Investigator). 1992 to 1995

(90-0234) Geometry of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1990 to 1992

(88-0222) Geometry of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1987 to 1990

(86-0080) Topology of Singular Spaces awarded by National Science Foundation (Principal Investigator). 1986 to 1988

Goresky, M, and Pardon, W. "Chern classes of automorphic vector bundles." *Inventiones Mathematicae* 147.3 (2002): 561-612.
Full Text

Pardon, W, and Stern, M. "Pure hodge structure on the L2-cohomology of varieties with isolated singularities." *Journal fur die Reine und Angewandte Mathematik* 533 (2001): 55-80.

Pardon, WL, and Stern, MA. "L2 -∂-cohomology of complex projective varieties." *Journal of the American Mathematical Society* 4.3 (January 1, 1991): 603-621.
Full Text

Pardon, WL. "Intersection homology Poincaré spaces and the characteristic variety theorem." *Commentarii Mathematici Helvetici* 65.1 (1990): 198-233.
Full Text

Pardon, WL. "The L2-∂-cohomology of an algebraic surface." *Topology* 28.2 (1989): 171-195.

Goresky, M, and Pardon, W. "Wu numbers of singular spaces." *Topology* 28.3 (1989): 325-367.
Full Text

Hsiang, WC, and Pardon, W. "When are topologically equivalent orthogonal transformations linearly equivalent?." *Inventiones Mathematicae* 68.2 (1982): 275-316.
Full Text

Pardon, W. "Mod 2 semi-characteristics and the converse to a theorem of Milnor." *Mathematische Zeitschrift* 171.3 (1980): 247-268.
Full Text

Bass, H, and Pardon, W. "Some hybrid symplectic group phenomena." *Journal of Algebra* 53.2 (1978): 327-333.

Pardon, W. "An invariant determining the Witt class of a unitary transformation over a semisimple ring." *Journal of Algebra* 44.2 (1977): 396-410.