A object of class 'moment', which is a list with three components:
momentthe input moment vector
representationa matrix containing the representation in terms of upper-triangular matrices
coefficientsthe coefficients corresponding to the rows of the representation
If the sum of the exponents is odd, returns -1 and prints "Sum of powers is odd. Moment is 0."
If any exponent is negative, returns -2 and prints "All components of the moment must be non-negative."
If any exponent is not an integer, returns -3 and prints "All components of the moment must be integers."