Nurmagambetov A. Duality-symmetric models of supergravity, M-theory and string theory

Thesis is devoted to studies of effective actions of M-theory/string theory, which take into account contributions of non-perturbative degrees of freedom of M-theory, and its hidden symmetry structure. Effective actions of M-theory solitons and related to them dual field theories are studied as well. Relations between different effective low-energy theories and their dimensionally reduced versions due to duality transformations are investigated. Models of superstrings with realistic critical dimension are proposed. The obtained results are important for deep understanding geometric and symmetric properties of super-p-branes, supergravity theories, relations between them and between corresponding dual field theories.