Dimensions of skew-shifted young diagrams and projective characters of the infinite symmetric group

We study a factorial of Schur's P-functions. In terms of these functions, we obtain an explicit formula for the dimension of a skew shifted Young diagram. The main application of this formula is a new derivation of the Nazarov's classification of indecomposable projective characters of an infinite symmetric group.Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 240, 1997, pp. 115–135.Supported by the Soros International Educational Program, grant 2093c.