We introduce the closed (resp. strongly closed) mu-unbounded filter CF
kappa lambdamu (resp. SCFkappa lambdamu) for a regular cardinal mu les
s than or equal to kappa, which is a mu-complete analog of the closed
(resp. strongly closed) unbounded filter on P(kappa)lambda. We give th
eir simple characterizations for the case mu = omega(1). We also study
generators of CFkappa lambdanu (resp. SCFkappa lambdanu) over CFkappa
lambdamu (resp. SCFkappa lambdamu) for the case omega < mu < nu v.