lambda: an integer partition, given as a vector of decreasing integers
algorithm: the algorithm used, either "DK" or "naive"
basis: the polynomial basis for algorithm = "naive", either "canonical" or "MSF" (monomial symmetric functions); for algorithm = "DK" the canonical basis is always used and this parameter is ignored
exact: logical, whether to get rational coefficients
Returns
A mvp multivariate polynomial (see mvp-package ), or a qspray multivariate polynomial if exact = TRUE and algorithm = "DK", or a character string if basis = "MSF".