Adam Peder Wie Sørensen (Oslo): Leavitt path algebras
Abstract: In the 1960's Leavitt studied rings with out the invariant basis property, in particular rings R such that R is isomorphic (as a module) to R^n for some n > 1. He showed that there exist universal rings with this properties, now called the Leavitt algebras. The defining relations of these algebra play a prominent role C*-algebra theory. In this talk I will explain Leavitt's construction, give a description of what C*-algebras are, and explain how the Leavitt relation have come to also be important in C*-algebra theory. I will not assume any knowledge of C*-algebras, but will assume a little familiarity with Hilbert spaces, i.e. what is l^2(N).