The Kondo effect in periodic narrow-band systems

The Kondo divergences owing to interaction of current carriers with local m oments in highly correlated electron systems are considered within the Hubb ard and s-d exchange models with infinitely strong on-site interaction, the many-electron Hubbard representation being used. The picture of density of states containing a peak at the Fermi level is obtained. Various forms of the self-consistent approximation are used. The problem of the violation of analytical properties of the Green's function is discussed. Smearing of th e "Kondo" peak owing to spin dynamics and finite temperatures is investigat ed.