def __init__(self):
r"""
TESTS::
sage: from sage.combinat.backtrack import PositiveIntegerSemigroup
sage: PP = PositiveIntegerSemigroup()
"""
SearchForest.__init__(self, facade = ZZ, category=(InfiniteEnumeratedSets(), CommutativeAdditiveSemigroups(), Monoids()))
def super_categories(self):
"""
EXAMPLES::
sage: CommutativeAdditiveMonoids().super_categories()
[Category of commutative additive semigroups]
"""
return [CommutativeAdditiveSemigroups()]