2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29728A system of strongly interacting fermions in a solid state is discussed. A structure of singlet and triplet coupled 2-particle states and their excitation spectra are investigated. It is shown that an account of intersite fermion interaction leads to new boson modes. A problem of interaction of pairs with external fields are discussed. The same analysis can be performed for another sorts of pairings like d-wave.16 pages, 3figuresCondensed Mattertext