Mitsunori Ogihara, Thomas Thierauf, Seinosuke Toda, and Osamu Watanabe
For any operator t on integer-valued functions,
we say that #P is closed under t in context
if, for every f in #P, t(f) belongs to PF^#P.
For several operators t,
it is shown that the closure properties of #P under
t in the above sense is closely related to the
relationships between PF^#P
and higher classes such as PH^PP and PP^PP.