ЗМІСТ

Honorary issues dedicated to the 60-th anniversary of Professor Ihor Stasyuk

Mancini F., Avella A.
Symmetries in the physics of strongly correlated electronic systems

Moskalenko V.A., Kon L.Z.
Diagram technique for the Hubbard model. Ladder diagram summation

Izyumov Yu.A., Chashchin N.I.
tJ -model in terms of equations with variational derivatives

Plakida N.M.
Spin-fluctuation superconductivity in the Hubbard model

Schürrer I., Schachinger E.
Constraints on possible mechanisms for high-T_c superconductivity

Robaszkiewicz S., Micnas R.
Superconductivity in systems with local attractive interactions

Loktev V.M., Turkowski V.M.
On temperature versus doping phase diagram of high critical temperature superconductors

Didukh L.
A modified form of the polar model of crystals

Rudavsky Yu., Ponedilok G., Dorosh L.
Long-wave spin excitations of crystalline s − d models

Vakarchuk I.O., Babin V.V.
Impurity effective mass in superfluid ⁴He

Bystrenko O., Zagorodny A.
Nonlinear phenomena in screening of highly charged grains in plasmas

Omelyan I.P., Mryglod I.M., Tokarchuk M.V.
Dielectric relaxation in dipolar fluids. Generalized mode approach