“…We also did not perform analyses of models with time dependent parameters which were studied by Mikhailov and Nögel (2003), Osajima (2007), Elices (2008), Benhamou, Gobet, and Miri (2010) etc. As mentioned in Bayer, Friz, and Gatheral (2016), the general overall shape of the volatility surface, with respect to equities, does not change in time significantly.…”