Department of Mathematics

University of Massachusetts, Lowell

One University Ave

Lowell, MA 01854

tel: (978) 934-2445

fax: (978) 934-3053

Click here for MATH 4260 Topology

Click here for MATH 3210 Discrete I

**Research interests:** topos theory, esp. its applications to model theory; algebraic topology

University of Washington Algebra Seminar, Seattle, Nov 2015.

Slides of my talk at the *Logic Colloquium* in Helsinki, Aug 2015.

An undergraduate talk on the vector-valued intermediate value theorem and the Brouwer fixed point theorem:

The sign pattern theorem given at *Budapest Semesters in Mathematics*, Spring 2013.

This is a pdf file of my talk at the *New Directions in the Model Theory of Fields* conference in Durham, July 2009.

*Elementary equivalences and accessible functors* (with J. Rosicky)

*The Grothendieck ring of varieties and of the theory of algebraically closed fields*

submitted to the Journal of Pure and Applied Algebra

*Cellular objects and Shelah's singular compactness theorem* (with J. Rosicky)

Journal of Pure and Applied Algebra vol.220 (2016), pp.1813-1836

*Abstract elementary classes and accessible categories* (with J. Rosicky)

Annals of Pure and Applied Logic vol.163 (2012), pp.2008-2017

*Topological invariance of the combinatorial Euler characteristic of o-minimal sets*

Homology, Homotopy and Applications vol.13 (2011), pp.165-174

*Zeta functions of equivalence relations over finite fields*

Finite Fields and Their Applications vol.17 (2011), pp.68-80

*Categorification, term rewriting and the Knuth--Bendix procedure*

Journal of Pure and Applied Algebra vol.215 (2011), pp.728-740

*Fibrations of simplicial sets*

Applied Categorical Structures vol.18 (2010), pp.505-516

*Isoperimetric inequalities and the Friedlander-Milnor conjecture*

Crelle's Journal vol.587 (2005), pp.27-47

*Higher Cech theory*

K-Theory vol.32 (2004), no.4, pp.293-322

*Simplicial torsors*

Theory and Applications of Categories vol.9 (2001), no.3, pp.43-60

*Theories of presheaf type*

Journal of Symbolic Logic vol.69 (2004), no.3, pp.923-934

*When is flatness coherent?* (with Karazeris and Rosicky)

Communications in Algebra vol.33 (2005), no.6, pp.1903-1912

*Sheafifiable homotopy model categories*

Math. Proc. Camb. Phil. Soc. vol.129 (2000), no.3, pp.447-475

*Sheafifiable homotopy model categories, Part II*

Journal of Pure and Applied Algebra vol.164 (2001), no.3, pp.307-324

*Operads from the viewpoint of categorical algebra*

in: Higher homotopy structures in topology and mathematical physics, pp.29-47.
Contemp. Math. 227, American Mathematical Society, 1999

*Homotopoi*
DVI file

Last update: March 8, 2016