The C*-algebra of a Single Invertible Element
  This paper characterizes the unital C*-algebra generated by a single invertible element as the unital free product of C[0,1] and C(T). To do this, I develop techniques to split and merge presentations of C*-algebras using free products in tandem with the Tietze transformations devised in my previous paper. 
Will Grilliette
math.OA