  The first part of the paper is devoted to two descriptions of all polynomial
tau-functions of the KP hierarchy: by a generalized Jacobi-Trudy formula, and a
generalized Giambelli formula. We use the latter formula in the second part to
obtain all polynomial tau-functions of the CKP hierarchy and its n-reductions.
In particular, for n=3 we find all polynomial tau-functions of the
Kaup-Kupershmidt hierarchy.
