“…For complex activation, holomorphic (a.k.a. analytic) function has been an important topic [Hitzer, 2013, Jalab and Ibrahim, 2011, Vitagliano et al, 2003, Kim and Adali, 2001, Mandic and Goh, 2009, Tripathi and Kalra, 2010 , since it makes the back-propagation simpler thus training becomes faster [Amin et al, 2011 . The importance of Complex Phase Angle of CANN has been suggested, including similarity to biological neuron [Reichert and Serre, 2013].…”