def __init__(self, X, Y, category=None, check=True, base=ZZ):
"""
The Python constructor.
INPUT:
The same as for any homset, see
:mod:`~sage.categories.homset`.
EXAMPLES::
sage: P1xP1 = toric_varieties.P1xP1()
sage: P1 = toric_varieties.P1()
sage: hom_set = P1xP1.Hom(P1); hom_set
Set of morphisms
From: 2-d CPR-Fano toric variety covered by 4 affine patches
To: 1-d CPR-Fano toric variety covered by 2 affine patches
An integral matrix defines a fan morphism, since we think of
the matrix as a linear map on the toric lattice. This is why
we need to ``register_conversion`` in the constructor
below. The result is::
sage: hom_set(matrix([[1],[0]]))
Scheme morphism:
From: 2-d CPR-Fano toric variety covered by 4 affine patches
To: 1-d CPR-Fano toric variety covered by 2 affine patches
Defn: Defined by sending Rational polyhedral fan in 2-d lattice N
to Rational polyhedral fan in 1-d lattice N.
"""
SchemeHomset_generic.__init__(self, X, Y, category=category, check=check, base=base)
self.register_conversion(MatrixSpace(ZZ, X.fan().dim(), Y.fan().dim()))
def __init__(self, X, Y, category=None, check=True, base=ZZ):
"""
The Python constructor.
INPUT:
The same as for any homset, see
:mod:`~sage.categories.homset`.
EXAMPLES::
sage: P1xP1 = toric_varieties.P1xP1()
sage: P1 = toric_varieties.P1()
sage: hom_set = P1xP1.Hom(P1); hom_set
Set of morphisms
From: 2-d CPR-Fano toric variety covered by 4 affine patches
To: 1-d CPR-Fano toric variety covered by 2 affine patches
An integral matrix defines a fan morphism, since we think of
the matrix as a linear map on the toric lattice. This is why
we need to ``register_conversion`` in the constructor
below. The result is::
sage: hom_set(matrix([[1],[0]]))
Scheme morphism:
From: 2-d CPR-Fano toric variety covered by 4 affine patches
To: 1-d CPR-Fano toric variety covered by 2 affine patches
Defn: Defined by sending Rational polyhedral fan in 2-d lattice N
to Rational polyhedral fan in 1-d lattice N.
"""
SchemeHomset_generic.__init__(self, X, Y, category=category, check=check, base=base)
self.register_conversion(MatrixSpace(ZZ, X.fan().dim(), Y.fan().dim()))
def __init__(self, X, S):
R = X.base_ring()
SchemeHomset_generic.__init__(self, spec.Spec(S, R), X)
P2 = X.curve()._printing_ring
if S != R:
y = str(P2.gen())
x = str(P2.base_ring().gen())
P1 = PolynomialRing(S,name=x)
P2 = PolynomialRing(P1,name=y)
self._printing_ring = P2
def __init__(self, X, S):
R = X.base_ring()
SchemeHomset_generic.__init__(self, spec.Spec(S, R), X)
P2 = X.curve()._printing_ring
if S != R:
y = str(P2.gen())
x = str(P2.base_ring().gen())
P1 = PolynomialRing(S, name=x)
P2 = PolynomialRing(P1, name=y)
self._printing_ring = P2