[GourionSeeger]_, whose elements' entries are in non-increasing
order::
- sage: set_random_seed()
sage: n = ZZ.random_element(10)
sage: K = schur_cone(n).dual()
sage: x = K.random_element()
The Schur cone induces the majorization ordering::
- sage: set_random_seed()
sage: def majorized_by(x,y):
....: return (all(sum(x[0:i]) <= sum(y[0:i])
....: for i in range(x.degree()-1))