I  am  Professor of mathematics and Chairman of the  mathematics department at the University at Buffalo, SUNY.    My office is 211 in the mathematics buildling and my office phone is 716-645-8775.

Spring 2013 Office Hours: 

                Monday: 2-3,  Thursday 3-4 or by appt.

Email me:  dhemmer@math.buffalo.edu                                

My CV:   Here is my CV as of May 2013.

My Research:
           
            Here is a  research statement  designed for those in my field.

            Here is a research statement designed to be accessible to undergraduate math majors.                                 

Publications:

• "The Ext¹  quiver for completely splittable representations of the symmetric group,"  Journal of Group Theory, (4)   (2001) #4, p. 401-416. pdf    dvi ps
• "Support varieties for modules over symmetric groups," (With Dan Nakano) Journal of Algebra, (254) (2002), p. 422-440. pdf
  
• "Specht filtrations for Hecke algebras of type A," (With Dan Nakano),  J. London Math Society (2) (69) (2004), p. 623-638. pdf
  
• "Fixed-point functors  for symmetric groups and Schur algebras," J. Algebra (280) (2004), p. 295-312.  pdf
• "A row removal theorem for the Ext^1 quiver of symmetric groups and Schur algebras,"  Proc. American Mathematical Society, ( 133)  (2005), p.403-414.   dvi     pdf
• "Representation Type of Schur Superalgebras," (With Kujawa and Nakano), J. Group Theory, (9) (2006) #3, p. 283-306.   pdf   ps
• "Irreducible Specht modules are signed Young modules," J. Algebra (305) (2006) , p.433-441  pdf
• "Cohomology of Specht modules," (with Nakano) J. Algebra (306)  (2006), p. 191-200.   pdf
  
• "Symmetric Group Modules with Specht and Dual Specht Filtrations," Communications in Algebra, 35:11, (2007) 3292 - 3306  pdf
  
• "Cohomology and generic cohomology of Specht modules for the symmetric group," J. Algebra (322) (2009),  1498-1515. pdf
• "The complexity of certain Specht modules for the symmetric group,"  Journal of Algebraic Combinatorics, (30) (2009), 421-427.  pdf
• "The group of endotrivial modules for the symmetric and alternating groups," (With Jon Carlson and Nadia Mazza), Proc. Edin. Math. Soc. (2010) 53, 83–95 .  pdf
• "On the cohomology of Young modules for the symmetric group," (With Fred Cohen and Dan Nakano), Advances in Mathematics (224) (2010), 1419-1461.   pdf
• "Stable decompositions for some symmetric group characters arising in braid group cohomology,"  Journal of Combinatorial Theory Series A, (118) (2011) 1136-1139.  pdf
• "A combinatorial approach to Specht module cohomology," Algebra Colloq. (19)  (2012) 777-786.   pdf
• "Realizing large gaps in cohomology for symmetric group modules," Algebra and Number Theory (6) 2012 825-832.  pdf
• "Frobenius twists in the representation theory of the symmetric group,"  Proceedings of Symposia in Pure Mathematics, (86) 2012 187-200.  pdf
  
  

• My doctoral disseration (final version! 6/01)  dvi ps

• American Contract Bridge League
• AMS Math on the Web
  
• Groups, Representations and Cohomology Preprint Archive