Seminar

Thursday, July 19, 2018 1:30 pm - 1:30 pm EDT (GMT -04:00)

Master's Project Presentation

Adam Humeniuk, Pure Mathematics, University of Waterloo

"Existence of the C*-envelope"

In 1969, Arveson defined the C*-envelope of an operator algebra or operator system as a universal quotient amongst all C*-algebras which contain it. He left the existence of the C*-envelope as an open problem. In a whirlwind tour of my Master's research paper, I'll discuss the diverse tools used to prove its existence in the intervening decades.

Thursday, January 12, 2017 4:00 pm - 4:00 pm EST (GMT -05:00)

Graduate Student Colloquium

Hongdi Huang, Pure Mathematics, University of Waterloo

"On *-clean group algebras"

A ring $R$ is called a $*$-ring (or a ring with involution $*$) if there exists an operation $*$: $R \rightarrow R$ such that $(x+y)^*=x^*+y^*, \,\ (xy)^*=y^*x^* \,\ $ and $(x^*)^*=x$,
for all $x, y\in R$.  An element in a ring $R$ is called $*$-clean if it is the sum of a unit and a projection ($*$-invariant idempotent). A $*$-ring is called $*$-clean if each of its elements is the sum of a unit and a projection.

Tuesday, January 10, 2017 3:00 pm - 3:00 pm EST (GMT -05:00)

Computability Learning Seminar

Mohammad Mahmoud, Pure Mathematics, University of Waterloo

"Existentially-atomic models"

We will talk about "Existentially atomic" and "Existentially algebraic" structures. We will give some examples and will show that being existentially algebraic implies being existentially atomic. As a particular example, we will prove a necessary and sufficient condition for a linear ordering to be existentially atomic.

Friday, January 13, 2017 3:30 pm - 3:30 pm EST (GMT -05:00)

Analysis Seminar

Ken Dykema, Texas A & M University

"Commuting operators in finite von Neumann algebras"

We find a joint spectral distribution measure for families
of commuting elements of a finite von Neumann algebra.  This
generalizes the Brown measure for single operators.  Furthermore, we
find a lattice (based on Borel sets) consisting of hyperinvariant
projections that decompose the spectral distribution measure.  This
leads to simultaneous upper triangularization results for commuting
operators.