PhD Defense: Matt Scalamandre - University of Notre Dame

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Location: 311 DeBartolo Hall

Photo of: Matt Scalamandre

Speaker: Matt Scalamandre
University of Notre Dame

Will give a PhD Defense entitled:
A Solomon-Tits theorem for rings

Abstract: An analogue of the Tits building is defined and studied for commutative rings. We prove a Solomon-Tits theorem when $R$ either satisfies a stable range condition, or is the ring of $S$-integers of a global field. We then define an analogue of the Steinberg module of $R$ and study it both as a $\mathbb{Z}$-module and as a representation. We find the rank of Steinberg when $R$ is a finite ring, and compute the length of $\text{St}_2(R)\otimes \mathbb{Q}$ as a $\text{GL}_2(R)$-representation when $R$ is uniserial. As an application of these results, we produce a lower bound for the rank of the top-dimensional cohomology of principal congruence subgroups of nonprime level

Date: 03-04-2024
Time: 12:00 pm
Location: 311 DeBartolo HallĀ 

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