This volume of the Encyclopaedia contains three contributions in the field of complex analysis; on mean periodicity and convolutionequations, Yang-Mills fields and the Radon-Penrose transform, and stringtheory. It is immensely useful to graduate students and researchers in complex analysis, differential geometry, quantum field theory, string theory and general relativity.

Plurisubharmonic functions playa major role in the theory of functions of several complex variables. The extensiveness of plurisubharmonic functions, the simplicity of their definition together with the richness of their properties and. most importantly, their close connection with holomorphic functions have assured plurisubharmonic functions a lasting place in multidimensional complex analysis. (Pluri)subharmonic functions first made their appearance in the works of Hartogs at the beginning of the century. They figure in an essential way, for example, in the proof of the famous theorem of Hartogs (1906) on joint holomorphicity. Defined at first on the complex plane IC, the class of subharmonic functions became thereafter one of the most fundamental tools in the investigation of analytic functions of one or several variables. The theory of subharmonic functions was developed and generalized in various directions: subharmonic functions in Euclidean space IRn, plurisubharmonic functions in complex space en and others. Subharmonic functions and the foundations ofthe associated classical poten tial theory are sufficiently well exposed in the literature, and so we introduce here only a few fundamental results which we require. More detailed expositions can be found in the monographs of Privalov (1937), Brelot (1961), and Landkof (1966). See also Brelot (1972), where a history of the development of the theory of subharmonic functions is given."

The first contribution describes basic concepts, facts and problems of the modern theory of entire functions of several complex variables. The second contribution deals with analogies of basic Nevanlinna's theorems about the distribution of values in the multidimensional case and various applications. The third contribution is devoted to invariant metrics and volumes and their applications in problems of function theory of several variables. The fourth contribution touches upon various results concerning the rigidity of holomorphic mappings of complex spaces beginnning with classical Liouville's and Picard's theorems. Contribution five presents results concerning extension of holomorphic mappings to the boundaries of domains, and results about correspondence of boundaries and equivalence of domains with respect to biholomorphic mappings. Contribution six dwells on the problem of biholomorphic equivalence of manifolds in this differential geometric aspect. The last contribution reviews applications of multidimensional complex geometry in modern physical theories - supergravitation and supergauge fields. This volume will be useful to complex analysts and physicists. It is rounded off by an extensive bibliography.

From the reviews: "... In sum, the volume under review is the first quarter of an important work that surveys an active branch of modern mathematics. Some of the individual articles are reminiscent in style of the early volumes of the first Ergebnisse series and will probably prove to be equally useful as a reference; ...for the appropriate reader, they will be valuable sources of information about modern complex analysis." Bulletin of the Am.Math.Society, 1991"... This remarkable book has a helpfully informal style, abundant motivation, outlined proofs followed by precise references, and an extensive bibliography; it will be an invaluable reference and a companion to modern courses on several complex variables." ZAMP, Zeitschrift für Angewandte Mathematik und Physik, 1990

This volume of the Encyclopaedia contains four parts each of which being an informative survey of a topic in the field of several complex variables. Thefirst deals with residue theory and its applications to integrals depending on parameters, combinatorial sums and systems of algebraic equations. The second part contains recent results in complex potential theory and the third part treats function theory in the unit ball covering research of the last twenty years. The latter part includes an up-to-date account of research related to a list of problems, which was published by Rudin in 1980. The last part of the book treats complex analysis in the futuretube. The future tube is an important concept in mathematical physics, especially in axiomatic quantum field theory, and it is related to Penrose'swork on "the complex geometry of the real world." Researchers and graduate students in complex analysis and mathematical physics will use thisbook as a reference and as a guide to exciting areas of research.

This volume of the Encyclopaedia contains three contributions in the field of complex analysis. The topics treated are mean periodicity and convolutionequations, Yang-Mills fields and the Radon-Penrose transform, and stringtheory. The latter two have strong links with quantum field theory and the theory of general relativity. In fact, the mathematical results described inthe book arose from the need of physicists to find a sound mathematical basis for their theories. The authors present their material in the formof surveys which provide up-to-date accounts of current research. The book will be immensely useful to graduate students and researchers in complex analysis, differential geometry, quantum field theory, string theoryand general relativity.