There are two ways that certain Fano fourfolds (for example, cubic fourfoldsand Gushel-Mukai fourfolds) can be associated with K3 surfaces. On the one
hand, we can associate a K3 surface to the fourfold Hodge-theoretically, meaning
the middle cohomology of the fourfold contains the middle cohomology of the K3
as a sub-Hodge structure; on the other hand, we can homologically associate a
K3 to the fourfold, which is to require the Kuznetsov component of the fourfolds
to be equivalent to the bounded derived of the K3. Conjecturally, one expect
such K3 associations detect rationality of the fourfolds. It has been proved that
for cubic fourfolds, these two types of K3 associations are equivalent, whereas for
Gushel-Mukai fourfolds, Hodge-association of a K3 strictly implies homological
association of a K3. We continue this line of study, instead of comparing fourfolds-
K3 association we consider fourfolds-fourfolds association. We prove that, at least
for a generic Gushel-Mukai fourfold in the Hodge-special loci, if it admits Hodgeassociated
cubic fourfolds, then it admits a homological-associated one, and vice
versa.