I am using gretl 1.6.6 now. It seems that the constant term in the
mean equation of ARCH/GARCH estimation is automatically added though
the default function by click \Model\Time series\ARCH or GARCH looks
that the const as a independant variable can be removed.
Is it required to have a constant term in the mean equation of
ARCH/GARCH? Is it possible to remove the constant term in the mean
equation with ARCH/GARCH estimation?
Chung Yuan Christian University, Taiwan