Mittag-Leffler function generalizes the exponential function. It plays an important role in fractional order dynamic systems.

Key reference:
A. A. KILBAS, M. SAIGOb, and R. K. SAXENA, “Generalized Mittag-Leffler function and generalized fractional calculus operators,” Integral Transforms and Special Functions, vol. 15, No. 1, 2004, pp. 31–49.

Based on the ml_fun.m code in Dingyu Xue, YangQuan Chen* and Derek Atherton. “Linear Feedback Control – Analysis and Design with Matlab”. SIAM Press, 2007, ISBN: 978-0-898716-38-2. (348 pages)