Godel incompleteness theorems and the limits of their applicability. I

This is a survey of results related to the Godel incompleteness theorems and the limits of their applicability. The first part of the paper discusses Godel's own formulations along with modern strengthenings of the first incompleteness theorem. Various forms and proofs of this theorem are compared. Incompleteness results related to algorithmic problems and mathematically natural examples of unprovable statements are discussed. Bibliography: 68 titles.