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Monday, February 1, 2021

**Abstract:** The classical definition of the space $GL_1(R)$ of units, given a ring spectrum $R$, does not play well with more modern models of spectra. In this talk, we will introduce Ando-Blumberg-Gepner-Hopkins-Rezk's Thom spectra functor, which builds upon a construction of $GL_1(R)$ as an $A_{\infty}$-space. If time permits, we will also briefly look at their $E_{\infty}$-version. Please email vb8 at illinois dot edu for the zoom details.