def multiply_variable(self, i): """ Returns the Schubert polynomial obtained by multiplying self by the variable `x_i`. EXAMPLES:: sage: X = SchubertPolynomialRing(ZZ) sage: a = X([3,2,4,1]) sage: a.multiply_variable(0) X[4, 2, 3, 1] sage: a.multiply_variable(1) X[3, 4, 2, 1] sage: a.multiply_variable(2) X[3, 2, 5, 1, 4] - X[3, 4, 2, 1] - X[4, 2, 3, 1] sage: a.multiply_variable(3) X[3, 2, 4, 5, 1] """ if isinstance(i, Integer): return symmetrica.mult_schubert_variable(self, i) else: raise TypeError, "i must be an integer"