By Alexandr A. Ovchinnikov, Ivan I. Ukrainskii
Advances within the physics and chemistry of low-dimensional platforms were relatively very good within the previous few many years. countless numbers of quasi-one-dimensional and quasi-two-dimensional structures were synthesized and studied. the most well-liked representatives of quasi-one-dimensional fabrics are polyacethylenes CH  and engaging in donor-acceptor molecular crystals TIF z TCNQ. Examples of quasi-two-dimensional structures are extreme temperature su perconductors (HTSC) in accordance with copper oxides LA2CU04, YBa2Cu306+y and natural superconductors in accordance with BEDT -TIP molecules. The houses of such one- and two-dimensional fabrics aren't but absolutely understood. at the one hand, the equations of movement of one-dimensional sys tems are fairly basic, which allows rigorous ideas of version difficulties. nevertheless, manifestations of assorted interactions in one-dimensional structures are particularly extraordinary. This refers, specifically, to electron--electron and electron-phonon interactions. Even in the restrict of a susceptible coupling con stant electron--electron correlations produce an power hole within the spectrum of one-dimensional metals implying a Mott transition from steel to semiconductor kingdom. In these kinds of circumstances perturbation conception is inapplicable. that's one of many major problems at the method in the direction of a complete concept of quasi-one-dimensional structures. - This assembly held on the Institute for Theoretical Physics in Kiev may perhaps 15-18 1990 was once dedicated to similar difficulties. The papers chosen for this quantity are grouped into 3 sections.