## Mathematics## Seminar |

## Rocky Mountain Algebraic Combinatorics Seminar

### Monodromy and K-theory of Schubert Curves via Generalized Jeu de Taquin

Maria Monks Gillespie

University Of California, Berkeley

Schubert curves are the spaces of solutions to certain one-dimensional
Schubert problems involving flags osculating the rational normal curve. The
real locus of a Schubert curve is known to be a natural covering space of
*RP*^{1}, so its real geometry is fully characterized by the monodromy of the
cover. It is also possible, using K-theoretic Schubert calculus, to relate
the real locus to the overall (complex) Riemann surface.

### Automorphisms of generalized Sylvester Hadamard matrices

Dane Flannery

National University of Ireland, Galway

Cocyclic development of pairwise combinatorial designs was discovered by Warwick de Launey and Kathy Horadam in the early 1990s. We first recount some algebraic essentials of the theory. Building on this, we proceed to discuss recent new results about the cocyclic development of a certain infinite family of generalized Hadamard matrices (which contain the Sylvester Hadamard matrix family as a special case). Specifically, we characterise the `indexing groups' of the matrices considered as cocyclic designs. Many open questions remain; we mention some of these. This is joint work with Ronan Egan (also at National University of Ireland, Galway).

Weber 223

4–6 pm

Friday, December 4, 2015

(Refreshments in Weber 117, 3:30–4 pm)

Colorado State University

This is a joint Denver U / UC Boulder / UC Denver / U of Wyoming / CSU seminar that meets biweekly. Anyone interested is welcome to join us at a local restaurant for dinner after the talks.