Phase separation in the strongly correlated Falicov-Kimball model in infinite dimensions is examined. We show that the phase separation can occur for any values of the interaction constant J <Superscript>*</Superscript> when the site energy ε <Superscript>0</Superscript> of the localized electrons is equal to zero. Electron-poor regions always...</superscript></superscript>

The events in Ukraine are in the thick of actuality, at the crossroads of East and West. From a buffer zone it has become an acute space of exhibition of Russia’s interests, on one side, and of the European Union’s, on the other side. As the EU does not have a unique army or a strong...