This volume continues the series of proceedings of summer schools on theoretical physics which aim at an adequate description of the structure of condensed matter in terms of sophisticated, advanced mathematical tools. This time, the main emphasis is put on the question of whether (and when) the energy bands in solids are continuous. Profs. L Michel, J Zak and others consider the origin, existence and continuity of band structure. Also, some previously discussed problems (magnetic symmetry, flux quantization, statistics, quasicrystals, the Bethe ansatz) are pursued further, and appropriate mathematical tools, rooted in “actions of groups on sets”, are developed.

This volume continues the series of proceedings of summer schools on theoretical physics related to various aspects of the structure of condensed matter, and to appropriate mathematical methods for an adequate description. Three main topics are covered: (i) symmetric and unitary groups versus electron correlations in multicentre systems; (ii) conformal symmetries, the Bethe ansatz and quantum groups; (iii) paradoxes of statistics, space-time, and time quantum mechanics. Problems considered in previous schools are merged with some new developments, like statistics with continuous Young diagrams, the existence and structure of energy bands in solids with fullerenes, membranes and some coverings of graphite sheets, or vortex condensates with quantum counterparts of Maxwell lows.

This volume provides an adequate mathematical description of solid state properties. It concentrates on group action methods, generalized statistics and molecular symmetries (unitary and symmetric groups).

These proceedings review the recent developments in current research connected with an adequate description of condensed matter in statistics of quasiparticles, topological invariants and self-similar structures.

This volume reviews some selected problems in solid state physics with an emphasis on adequate mathematical tools. The three main subjects are magnetic structures and neutron scattering; Berry phases and energy bands in solids (symmetry, analicity, Hofstadter butterfly, van Hove singularities); and quasicrystals, finite systems, and group action on sets (unitary group approach, Schur functions). Software presentations are included as a separate part.

This volume continues the series of proceedings of summer schools on theoretical physics related to various aspects of the structure of condensed matter, and to appropriate mathematical methods for an adequate description. Three main topics are covered: (i) symmetric and unitary groups versus electron correlations in multicentre systems; (ii) conformal symmetries, the Bethe ansatz and quantum groups; (iii) paradoxes of statistics, space-time, and time quantum mechanics. Problems considered in previous schools are merged with some new developments, like statistics with continuous Young diagrams, the existence and structure of energy bands in solids with fullerenes, membranes and some coverings of graphite sheets, or vortex condensates with quantum counterparts of Maxwell lows.

At the crossing of centuries, it is very important to review the main problems and research in theoretical physics. This was the purpose of the International Workshop on Frontiers of Theoretical Physics, allowing the interchange of ideas among people with different expertise.The proceedings can be divided into two parts: (1) general view talks about string, particle physics, nuclear physics, etc. given by Profs. T Yoneya, M Kobayazhi, A Sanda, Z Li and F Sakata; (2) research related to many important fields, such as quantum field theory, string theory, particle physics, condensed matter physics, nuclear physics and mathematical physics.

Volume III/28 is a supplement to volume III/16a+b Ferroelectrics and Related Substances. It also consists of two parts a and b. The present subvolume III/28a contains data on ferroelectric oxides, supplementing III/16a which appeared in 1981. Subvolume III/28b, due in 1990, will cover non-oxides, supplementing III/16b (published in 1982). Reliable data on both pure compounds and solid solutions, published mostly between 1978 and 1986 and some data from the literature up to early 1988 are critically evaluated and included. The dielectric and ferroelectric behaviour, as well as all other properties relevant to the characterization of these substances are presented in tables and figures. About 22,000 references have been surveyed with the aid of a computer. All values are given in SI units. Rapid localization of the required data is facilitated by an alphabetical index of substances and a two-dimensional survey of substances and properties dealt with in both subvolumes III/28a and III/16a.

Volume III/28 is a supplement to volume III/16a+b Ferroelectrics and Related Substances. It also consists of two parts a and b. Subvolume III/28a which came out in December 1989, contains data on ferroelectric oxides, supplementing III/16a which appeared in 1981. The present subvolume III/28b covers non-oxides, supplementing III/16b (published in 1982). Reliable data on both pure compounds and solid solutions, published mostly between 1978 and 1986 and some data from the literature up to early 1988 are critically evaluated and included. The dielectric and ferroelectric behaviour, as well as all other properties relevant to the characterization of these substances are presented in tables and figures. About 22,000 references have been surveyed with the aid of a computer. All values are given in SI units. Rapid localization of the required data is facilitated by an alphabetical index of substances and a two-dimensional survey of substances and properties dealt with in both subvolumes III/28b and III/16b.