New Open Problems Related to Old Conjectures by Helleseth
  Recently, very interesting results have been obtained concerning the Fourier spectra of power permutations over a finite field. In this note we survey the recent ideas of Aubry, Feng, Katz, and Langevin, and we pose new open problems related to old conjectures proposed by Helleseth in the middle of the seventies. 
Daniel J. Katz and Philippe Langevin
math.NT cs.IT math.IT