${\rm GL}(3)$-Based Quantum Integrable Composite Models. II. Form Factors of Local Operators

We study integrable models solvable by the nested algebraic Bethe ansatz and possessing the ${\rm GL}(3)$-invariant $R$-matrix. We consider a composite model where the total monodromy matrix of the model is presented as a product of two partial monodromy matrices. Assuming that the last ones can be expanded into series with respect to the inverse spectral parameter we calculate matrix elements of the local operators in the basis of the transfer matrix eigenstates. We obtain determinant representations for these matrix elements. Thus, we solve the inverse scattering problem in a weak sense.