We present the basic elements of a generalization of symmetric function
theory involving functions of commuting and anticommuting (Grassmannian)
variables. These new functions, called symmetric functions in superspace, are
invariant under the diagonal action of the symmetric group on the sets of
commuting and anticommuting variables. In this work, we present the superspace
extension of the classical bases, namely, the monomial symmetric functions, the
elementary symmetric functions, the completely symmetric functions, and the
power sums. Various basic results, such as the generating functions for the
multiplicative bases, Cauchy formulas, involution operations as well as the
combinatorial scalar product are also generalized.Comment: 21 pages, this supersedes the first part of math.CO/041230