Background
I hail from Bucharest, Romania. I did my undergraduate studies at the Faculty of Mathematics of the University of Bucharest. Here is a picture from those days.
For my graduate studies, I went to Columbia University, receiving my Ph.D. degree in 1984. Here is a picture from around that time, taken in Cambridge, UK.
After a J.W. Gibbs Instructorship at Yale University, I came in 1986 to Northeastern University, where I've been ever since.
Research
My research interests are in Topology, and how it relates to Algebra, Geometry, and Combinatorics.
I currently investigate cohomology jumping loci, and their applications to algebraic varieties, lowdimensional
topology, and toric topology, such as the study of hyperplane arrangements, moment angle complexes,
configuration spaces, and various classes of knots, links, and manifolds, as well as the homology
and lower central series of discrete groups. Below are some recent papers and preprints
(click here for a complete list).

Resonance varieties and DwyerFried invariants, in: Arrangements of Hyperplanes (Sapporo 2009), 359398, Adv. Stud. Pure Math., vol. 62, Kinokuniya, Tokyo, 2012.

Geometric and homological finiteness in free abelian covers, in: Configuration Spaces: Geometry,
Combinatorics and Topology (Centro De Giorgi, 2010), 461501, Publications of the Scuola Normale Superiore, vol. 14, Edizioni della Normale, Pisa, 2012.

Homological finiteness in the Johnson filtration of the automorphism group of a free group (with S. Papadima), Journal of Topology 5 (2012), no. 4, 909944

The rational homology of real toric manifolds, extended abstract of a talk given at MFO, in: Oberwolfach Reports 9 (2012), no. 4, 29722976.

Intersections of translated algebraic subtori (with Y. Yang and G. Zhao), J. Pure and Appl. Algebra 217 (2013), no. 3, 481494.

Characteristic varieties and Betti numbers of free abelian covers, Int. Math. Res. Notices (IMRN) 2014 (2014), no. 4, 10631124.

Kähler groups, quasiprojective groups, and 3manifold groups (with S. Friedl), J. London Math. Soc. 89 (2014), no. 1, 151168.

Hyperplane arrangements and Milnor fibrations, Ann. Fac. Sci. Toulouse 23 (2014), no. 2, 417481.

Multinets, parallel connections, and Milnor fibrations of arrangements (with G. Denham), Proc. London Math. Soc. 108 (2014) no. 6, 14351470.

Nonabelian resonance: product and coproduct formulas (with S. Papadima), in Bridging Algebra, Geometry, and Topology,
Springer Proceedings in Mathematics and Statistics, vol. 96, 2014, pp 269280.

Jump loci in the equivariant spectral sequence (with S. Papadima), Math. Res. Lett. 21 (2014), no. 2, 863883.

Vanishing resonance and representations of Lie algebras (with S. Papadima), to appear in Crelle's Journal.

Homological finiteness of abelian covers (with Y. Yang and G. Zhao), to appear in Ann. Sc. Norm. Super. Pisa.

Algebraic models, Alexandertype invariants, and GreenLazarsfeld sets (with A. Dimca and S. Papadima), to appear in Bull. Math. Soc. Sci. Math. Roumanie.

Flat connections and resonance varieties: from rank one to higher ranks (with A.D. Macinic, S. Papadima, C.R. Popescu), preprint Dec. 2013.

The Milnor fibration of a hyperplane arrangement: from modular resonance to algebraic monodromy (with S. Papadima), preprint Jan. 2014, revised April 2014.

Combinatorial covers and vanishing cohomology (with G. Denham and S. Yuzvinsky), preprint Nov. 2014.

Around the tangent cone theorem, preprint Jan. 2015.
Teaching
I teach a variety of math courses, both at the undergraduate and graduate level. If you are interested in taking a directed study course or a reading course with me (in addition to those courses regularly offered), please contact me.

In Spring 2011, I taught MATH 3150, an undergraduate course in Real Analysis; MATH 5121, a graduate Topology 1 course; and MATH 7722, a Readings in Algebraic Topology course.

In Fall 2011, I taught MATH 3150, an undergraduate course in Real Analysis; MATH 7221, a graduate course in Topology 2; and MATH 7321, a graduate course in Topology 3.

In Spring 2012, I taught MATH 7722, a Readings in Algebraic Topology course, and MATH 7723, a Readings in Geometric Topology course.

In Fall 2012, I taught MATH 7723, a Readings in Geometric Topology course, and MATH 9990, a Dissertation course.

In Spring 2013, I taught MATH 2351,
an undergraduate course in Ordinary Differential Equations, MATH 5121,
a graduate Topology 1 course, MATH 7722,
a Readings in Algebraic Topology course, and MATH 9996, a Dissertation Continuation course.

In Spring 2014, I taught MATH 4565, an undergraduate course in Topology, and MATH 9996, a Dissertation Continuation course.

In Fall 2014, I taught MATH 3150, an undergraduate course in Real Analysis,
MATH 7221, a graduate course in Topology 2, and MATH 9996, a Dissertation Continuation course.

In Spring 2015, I teach MATH 4970, a Senior Honors Project in Knot Theory, and MATH 9996, a Dissertation Continuation course.