# Operator Algebra Seminars

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Fri., Oct. 19, 2018 1:30 p.m.
- Fri., Oct. 19, 2018 2:30 p.m.
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Location: Classroom Building (CL) 416
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**Speaker:** Kenneth R. Davidson, University of Waterloo

**Title:** Free Semigroupoid Algebras

**Abstract:**

A free semigroupoid algebra is the WOT-closure of the algebra generated by a Toeplitz-Cuntz-Kreiger family of a graph. We obtain a structure theory for these algebras analogous to that of free semigroup algebra. These results are applied to obtain a Lebesgue-von Neumann-Wold decomposition of TCK families, along with reflexivity, a Kaplansky density theorem and classification for free semigroupoid algebras. Several classes of examples are discussed.

This is joint work with Adam Dor-On and Boyu Li.