Spectra of fuzzy sets of $S^1$
  In this article we explore some aspects of Fourier analysis on fuzzy sets. This work was part of a broader project jointly with Professor Vittorio Cafagna which spanned over a few years between 1998 and 2005. Professor Cafagna passed away unexpectedly in 2007. His intellectual breadth and inspiring passion for mathematics is still very well alive today. 
Vittorio Cafagna, Gianluca Caterina
math.CA math.LO