FRACTIONAL DIFFERENTIAL EQUATIONS

"In his discovery of calculus. Leibnitz first introduced the idea of a symbolic method and used the symbol dry drn = Dy for the nth order derivative, where n is a non-negative in- teger. L'Hospital asked Leibniz about the possibility of n 1 be a fraction, What if n = ?". Leibniz (1695) replied. It 2 will lead to an apparent paradox'. But he added propheti- cally. From this paradox, one day useful consequences will be drawn." --GOTTFRIED LEIBNIZ.