def octants(self):
assert self._degrees.is_finite()
from sage.combinat.posets.posets import Poset
def pocom(a, b):
t1, e1, s1 = a
t2, e2, s2 = b
if (t1 in (t2, 0)) and (e1 in (e2, 0)) and (s1 in (s2, 0)):
return True
return False
X = Poset(([(sgn(t), sgn(e), sgn(s)) for (t, e, s) in self._degrees], pocom))
return [list(u) for u in X.maximal_elements()]
