ON THE MANIFESTATION OF SYMMETRY AND DIMENSIONALITY FOR ELECTRONIC SYSTEMS IN LIFSHITZ TOPOLOGICAL TRANSITIONS

An effect of dimensionality and symmetry of the electronic system on t he order of the topological transitions is discussed. The difference b etween various types of transitions is explained in terms of symmetry. This is the first time the De Haas-van Alphen effect is treated as 1 1/2 order topological transition in the framework of the scheme propos ed. The case of an arbitrary dimensionality is discussed.