Relativistic equations with fractional and pseudo-differential operators
  In this paper we use different techniques from the fractional and pseudo-operators calculus to solve partial differential equations involving operators with non integer exponents. We apply the method to equations resembling generalizations of the heat equations and discuss the possibility of extending the procedure to the relativistic Schr\"odinger and Dirac equations. 
D. Babusci, G. Dattoli, M. Quattromini
math-ph hep-th math.MP