class AlgebraicWeight(WeightCharacter):
r"""
A point in weight space corresponding to a locally algebraic character, of
the form `x \mapsto \chi(x) x^k` where `k` is an integer and `\chi` is a
Dirichlet character modulo `p^n` for some `n`.
TESTS::
sage: w = pAdicWeightSpace(23)(12, DirichletGroup(23, QQ).0) # exact
sage: w == loads(dumps(w))
True
sage: w = pAdicWeightSpace(23)(12, DirichletGroup(23, Qp(23)).0) # inexact
sage: w == loads(dumps(w))
True
sage: w is loads(dumps(w)) # elements are not globally unique
False
"""
def __init__(self, parent, k, chi=None):
r"""
Create a locally algebraic weight-character.
EXAMPLES::
sage: pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0)
(13, 29, [2 + 2*29 + ... + O(29^20)])
"""
WeightCharacter.__init__(self, parent)
k = ZZ(k)
self._k = k
if chi is None:
chi = trivial_character(self._p, QQ)
n = ZZ(chi.conductor())
if n == 1:
n = self._p
if not n.is_power_of(self._p):
raise ValueError, "Character must have %s-power conductor" % p
self._chi = DirichletGroup(n, chi.base_ring())(chi)
def __call__(self, x):
r"""
Evaluate this character at an element of `\ZZ_p^\times`.
EXAMPLES:
Exact answers are returned when this is possible::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, QQ).0)
sage: kappa(1)
1
sage: kappa(0)
0
sage: kappa(12)
-106993205379072
sage: kappa(-1)
-1
sage: kappa(13 + 4*29 + 11*29^2 + O(29^3))
9 + 21*29 + 27*29^2 + O(29^3)
When the character chi is defined over a p-adic field, the results returned are inexact::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa(1)
1 + O(29^20)
sage: kappa(0)
0
sage: kappa(12)
17 + 11*29 + 7*29^2 + 4*29^3 + 5*29^4 + 2*29^5 + 13*29^6 + 3*29^7 + 18*29^8 + 21*29^9 + 28*29^10 + 28*29^11 + 28*29^12 + 28*29^13 + 28*29^14 + 28*29^15 + 28*29^16 + 28*29^17 + 28*29^18 + 28*29^19 + O(29^20)
sage: kappa(12) == -106993205379072
True
sage: kappa(-1) == -1
True
sage: kappa(13 + 4*29 + 11*29^2 + O(29^3))
9 + 21*29 + 27*29^2 + O(29^3)
"""
if isinstance(x, pAdicGenericElement):
if x.parent().prime() != self._p:
raise TypeError, "x must be an integer or a %s-adic integer" % self._p
if self._p**(x.precision_absolute()) < self._chi.conductor():
raise Exception, "Precision too low"
xint = x.lift()
else:
xint = x
if (xint % self._p == 0): return 0
return self._chi(xint) * x**self._k
def k(self):
r"""
If this character is `x \mapsto x^k \chi(x)` for an integer `k` and a
Dirichlet character `\chi`, return `k`.
EXAMPLE::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa.k()
13
"""
return self._k
def chi(self):
r"""
If this character is `x \mapsto x^k \chi(x)` for an integer `k` and a
Dirichlet character `\chi`, return `\chi`.
EXAMPLE::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa.chi()
Dirichlet character modulo 29 of conductor 29 mapping 2 |--> 28 + 28*29 + 28*29^2 + ... + O(29^20)
"""
return self._chi
def _repr_(self):
r"""
String representation of self.
EXAMPLES::
sage: pAdicWeightSpace(17)(2)._repr_()
'2'
sage: pAdicWeightSpace(17)(2, DirichletGroup(17, QQ).0)._repr_()
'(2, 17, [-1])'
sage: pAdicWeightSpace(17)(2, DirichletGroup(17, QQ).0^2)._repr_()
'2'
"""
if self._chi.is_trivial():
return "%s" % self._k
else:
return "(%s, %s, %s)" % (self._k, self._chi.modulus(), self._chi._repr_short_())
def teichmuller_type(self):
r"""
Return the Teichmuller type of this weight-character `\kappa`, which is
the unique `t \in \ZZ/(p-1)\ZZ` such that `\kappa(\mu) =
\mu^t` for \mu a `(p-1)`-st root of 1.
For `p = 2` this doesn't make sense, but we still want the Teichmuller
type to correspond to the index of the component of weight space in
which `\kappa` lies, so we return 1 if `\kappa` is odd and 0 otherwise.
EXAMPLE::
sage: pAdicWeightSpace(11)(2, DirichletGroup(11,QQ).0).teichmuller_type()
7
sage: pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0).teichmuller_type()
14
sage: pAdicWeightSpace(2)(3, DirichletGroup(4,QQ).0).teichmuller_type()
0
"""
# Special case p == 2
if self._p == 2:
if self.is_even():
return IntegerModRing(2)(0)
else:
return IntegerModRing(2)(1)
m = IntegerModRing(self._p).multiplicative_generator()
x = [y for y in IntegerModRing(self._chi.modulus()) if y == m and y**(self._p - 1) == 1]
if len(x) != 1: raise ArithmeticError
x = x[0]
f = IntegerModRing(self._p)(self._chi(x)).log(m)
return IntegerModRing(self._p - 1)(self._k + f)
def Lvalue(self):
r"""
Return the value of the p-adic L-function of `\QQ` evaluated at
this weight-character. If the character is `x \mapsto x^k \chi(x)`
where `k > 0` and `\chi` has conductor a power of `p`, this is an
element of the number field generated by the values of `\chi`, equal to
the value of the complex L-function `L(1-k, \chi)`. If `\chi` is
trivial, it is equal to `(1 - p^{k-1})\zeta(1-k)`.
At present this is not implemented in any other cases, except the
trivial character (for which the value is `\infty`).
TODO: Implement this more generally using the Amice transform machinery
in sage/schemes/elliptic_curves/padic_lseries.py, which should clearly
be factored out into a separate class.
EXAMPLES::
sage: pAdicWeightSpace(7)(4).Lvalue() == (1 - 7^3)*zeta__exact(-3)
True
sage: pAdicWeightSpace(7)(5, DirichletGroup(7, Qp(7)).0^4).Lvalue()
0
sage: pAdicWeightSpace(7)(6, DirichletGroup(7, Qp(7)).0^4).Lvalue()
1 + 2*7 + 7^2 + 3*7^3 + 3*7^5 + 4*7^6 + 2*7^7 + 5*7^8 + 2*7^9 + 3*7^10 + 6*7^11 + 2*7^12 + 3*7^13 + 5*7^14 + 6*7^15 + 5*7^16 + 3*7^17 + 6*7^18 + O(7^19)
"""
if self._k > 0:
return -self._chi.bernoulli(self._k)/self._k
if self.is_trivial():
return Infinity
else:
raise NotImplementedError, "Don't know how to compute value of this L-function"
def dimension_new_cusp_forms(self, k=2, eps=None, p=0, algorithm="CohenOesterle"):
r"""
Dimension of the new subspace (or `p`-new subspace) of cusp forms of
weight `k` and character `\varepsilon`.
INPUT:
- ``k`` - an integer (default: 2)
- ``eps`` - a Dirichlet character
- ``p`` - a prime (default: 0); just the `p`-new subspace if given
- ``algorithm`` - either "CohenOesterle" (the default) or "Quer". This
specifies the method to use in the case of nontrivial character:
either the Cohen--Oesterle formula as described in Stein's book, or
by Moebius inversion using the subgroups GammaH (a method due to
Jordi Quer).
EXAMPLES::
sage: G = DirichletGroup(9)
sage: eps = G.0^3
sage: eps.conductor()
3
sage: [Gamma1(9).dimension_new_cusp_forms(k, eps) for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
sage: [Gamma1(9).dimension_cusp_forms(k, eps) for k in [2..10]]
[0, 0, 0, 2, 0, 4, 0, 6, 0]
sage: [Gamma1(9).dimension_new_cusp_forms(k, eps, 3) for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
Double check using modular symbols (independent calculation)::
sage: [ModularSymbols(eps,k,sign=1).cuspidal_subspace().new_subspace().dimension() for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
sage: [ModularSymbols(eps,k,sign=1).cuspidal_subspace().new_subspace(3).dimension() for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
Another example at level 33::
sage: G = DirichletGroup(33)
sage: eps = G.1
sage: eps.conductor()
11
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1) for k in [2..4]]
[0, 4, 0]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1, algorithm="Quer") for k in [2..4]]
[0, 4, 0]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1^2) for k in [2..4]]
[2, 0, 6]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1^2, p=3) for k in [2..4]]
[2, 0, 6]
"""
if eps == None:
return GammaH_class.dimension_new_cusp_forms(self, k, p)
N = self.level()
eps = DirichletGroup(N)(eps)
from all import Gamma0
if eps.is_trivial():
return Gamma0(N).dimension_new_cusp_forms(k, p)
from congroup_gammaH import mumu
if p == 0 or N%p != 0 or eps.conductor().valuation(p) == N.valuation(p):
D = [eps.conductor()*d for d in divisors(N//eps.conductor())]
return sum([Gamma1_constructor(M).dimension_cusp_forms(k, eps.restrict(M), algorithm)*mumu(N//M) for M in D])
eps_p = eps.restrict(N//p)
old = Gamma1_constructor(N//p).dimension_cusp_forms(k, eps_p, algorithm)
return self.dimension_cusp_forms(k, eps, algorithm) - 2*old
def dimension_new_cusp_forms(self,
k=2,
eps=None,
p=0,
algorithm="CohenOesterle"):
r"""
Dimension of the new subspace (or `p`-new subspace) of cusp forms of
weight `k` and character `\varepsilon`.
INPUT:
- ``k`` - an integer (default: 2)
- ``eps`` - a Dirichlet character
- ``p`` - a prime (default: 0); just the `p`-new subspace if given
- ``algorithm`` - either "CohenOesterle" (the default) or "Quer". This
specifies the method to use in the case of nontrivial character:
either the Cohen--Oesterle formula as described in Stein's book, or
by Möbius inversion using the subgroups GammaH (a method due to
Jordi Quer).
EXAMPLES::
sage: G = DirichletGroup(9)
sage: eps = G.0^3
sage: eps.conductor()
3
sage: [Gamma1(9).dimension_new_cusp_forms(k, eps) for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
sage: [Gamma1(9).dimension_cusp_forms(k, eps) for k in [2..10]]
[0, 0, 0, 2, 0, 4, 0, 6, 0]
sage: [Gamma1(9).dimension_new_cusp_forms(k, eps, 3) for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
Double check using modular symbols (independent calculation)::
sage: [ModularSymbols(eps,k,sign=1).cuspidal_subspace().new_subspace().dimension() for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
sage: [ModularSymbols(eps,k,sign=1).cuspidal_subspace().new_subspace(3).dimension() for k in [2..10]]
[0, 0, 0, 2, 0, 2, 0, 2, 0]
Another example at level 33::
sage: G = DirichletGroup(33)
sage: eps = G.1
sage: eps.conductor()
11
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1) for k in [2..4]]
[0, 4, 0]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1, algorithm="Quer") for k in [2..4]]
[0, 4, 0]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1^2) for k in [2..4]]
[2, 0, 6]
sage: [Gamma1(33).dimension_new_cusp_forms(k, G.1^2, p=3) for k in [2..4]]
[2, 0, 6]
"""
if eps is None:
return GammaH_class.dimension_new_cusp_forms(self, k, p)
N = self.level()
eps = DirichletGroup(N, eps.base_ring())(eps)
if eps.is_trivial():
from .all import Gamma0
return Gamma0(N).dimension_new_cusp_forms(k, p)
from .congroup_gammaH import mumu
if p == 0 or N % p != 0 or eps.conductor().valuation(p) == N.valuation(
p):
D = [eps.conductor() * d for d in divisors(N // eps.conductor())]
return sum([
Gamma1_constructor(M).dimension_cusp_forms(
k, eps.restrict(M), algorithm) * mumu(N // M) for M in D
])
eps_p = eps.restrict(N // p)
old = Gamma1_constructor(N // p).dimension_cusp_forms(
k, eps_p, algorithm)
return self.dimension_cusp_forms(k, eps, algorithm) - 2 * old
class AlgebraicWeight(WeightCharacter):
r"""
A point in weight space corresponding to a locally algebraic character, of
the form `x \mapsto \chi(x) x^k` where `k` is an integer and `\chi` is a
Dirichlet character modulo `p^n` for some `n`.
TESTS::
sage: w = pAdicWeightSpace(23)(12, DirichletGroup(23, QQ).0) # exact
sage: w == loads(dumps(w))
True
sage: w = pAdicWeightSpace(23)(12, DirichletGroup(23, Qp(23)).0) # inexact
sage: w == loads(dumps(w))
True
sage: w is loads(dumps(w)) # elements are not globally unique
False
"""
def __init__(self, parent, k, chi=None):
r"""
Create a locally algebraic weight-character.
EXAMPLES::
sage: pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0)
(13, 29, [2 + 2*29 + ... + O(29^20)])
"""
WeightCharacter.__init__(self, parent)
k = ZZ(k)
self._k = k
if chi is None:
chi = trivial_character(self._p, QQ)
n = ZZ(chi.conductor())
if n == 1:
n = self._p
if not n.is_power_of(self._p):
raise ValueError("Character must have %s-power conductor" % p)
self._chi = DirichletGroup(n, chi.base_ring())(chi)
def __call__(self, x):
r"""
Evaluate this character at an element of `\ZZ_p^\times`.
EXAMPLES:
Exact answers are returned when this is possible::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, QQ).0)
sage: kappa(1)
1
sage: kappa(0)
0
sage: kappa(12)
-106993205379072
sage: kappa(-1)
-1
sage: kappa(13 + 4*29 + 11*29^2 + O(29^3))
9 + 21*29 + 27*29^2 + O(29^3)
When the character chi is defined over a p-adic field, the results returned are inexact::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa(1)
1 + O(29^20)
sage: kappa(0)
0
sage: kappa(12)
17 + 11*29 + 7*29^2 + 4*29^3 + 5*29^4 + 2*29^5 + 13*29^6 + 3*29^7 + 18*29^8 + 21*29^9 + 28*29^10 + 28*29^11 + 28*29^12 + 28*29^13 + 28*29^14 + 28*29^15 + 28*29^16 + 28*29^17 + 28*29^18 + 28*29^19 + O(29^20)
sage: kappa(12) == -106993205379072
True
sage: kappa(-1) == -1
True
sage: kappa(13 + 4*29 + 11*29^2 + O(29^3))
9 + 21*29 + 27*29^2 + O(29^3)
"""
if isinstance(x, pAdicGenericElement):
if x.parent().prime() != self._p:
raise TypeError("x must be an integer or a %s-adic integer" %
self._p)
if self._p**(x.precision_absolute()) < self._chi.conductor():
raise PrecisionError("Precision too low")
xint = x.lift()
else:
xint = x
if (xint % self._p == 0): return 0
return self._chi(xint) * x**self._k
def k(self):
r"""
If this character is `x \mapsto x^k \chi(x)` for an integer `k` and a
Dirichlet character `\chi`, return `k`.
EXAMPLES::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa.k()
13
"""
return self._k
def chi(self):
r"""
If this character is `x \mapsto x^k \chi(x)` for an integer `k` and a
Dirichlet character `\chi`, return `\chi`.
EXAMPLES::
sage: kappa = pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0^14)
sage: kappa.chi()
Dirichlet character modulo 29 of conductor 29 mapping 2 |--> 28 + 28*29 + 28*29^2 + ... + O(29^20)
"""
return self._chi
def __hash__(self):
r"""
TESTS::
sage: w = pAdicWeightSpace(23)(12, DirichletGroup(23, QQ).0)
sage: hash(w)
2363715643371367891 # 64-bit
-1456525869 # 32-bit
"""
if self._chi.is_trivial():
return hash(self._k)
else:
return hash((self._k, self._chi.modulus(), self._chi))
def _repr_(self):
r"""
String representation of self.
EXAMPLES::
sage: pAdicWeightSpace(17)(2)._repr_()
'2'
sage: pAdicWeightSpace(17)(2, DirichletGroup(17, QQ).0)._repr_()
'(2, 17, [-1])'
sage: pAdicWeightSpace(17)(2, DirichletGroup(17, QQ).0^2)._repr_()
'2'
"""
if self._chi.is_trivial():
return "%s" % self._k
else:
return "(%s, %s, %s)" % (self._k, self._chi.modulus(),
self._chi._repr_short_())
def teichmuller_type(self):
r"""
Return the Teichmuller type of this weight-character `\kappa`, which is
the unique `t \in \ZZ/(p-1)\ZZ` such that `\kappa(\mu) =
\mu^t` for \mu a `(p-1)`-st root of 1.
For `p = 2` this doesn't make sense, but we still want the Teichmuller
type to correspond to the index of the component of weight space in
which `\kappa` lies, so we return 1 if `\kappa` is odd and 0 otherwise.
EXAMPLES::
sage: pAdicWeightSpace(11)(2, DirichletGroup(11,QQ).0).teichmuller_type()
7
sage: pAdicWeightSpace(29)(13, DirichletGroup(29, Qp(29)).0).teichmuller_type()
14
sage: pAdicWeightSpace(2)(3, DirichletGroup(4,QQ).0).teichmuller_type()
0
"""
# Special case p == 2
if self._p == 2:
if self.is_even():
return IntegerModRing(2)(0)
else:
return IntegerModRing(2)(1)
m = IntegerModRing(self._p).multiplicative_generator()
x = [
y for y in IntegerModRing(self._chi.modulus())
if y == m and y**(self._p - 1) == 1
]
if len(x) != 1: raise ArithmeticError
x = x[0]
f = IntegerModRing(self._p)(self._chi(x)).log(m)
return IntegerModRing(self._p - 1)(self._k + f)
def Lvalue(self):
r"""
Return the value of the p-adic L-function of `\QQ` evaluated at
this weight-character. If the character is `x \mapsto x^k \chi(x)`
where `k > 0` and `\chi` has conductor a power of `p`, this is an
element of the number field generated by the values of `\chi`, equal to
the value of the complex L-function `L(1-k, \chi)`. If `\chi` is
trivial, it is equal to `(1 - p^{k-1})\zeta(1-k)`.
At present this is not implemented in any other cases, except the
trivial character (for which the value is `\infty`).
TODO: Implement this more generally using the Amice transform machinery
in sage/schemes/elliptic_curves/padic_lseries.py, which should clearly
be factored out into a separate class.
EXAMPLES::
sage: pAdicWeightSpace(7)(4).Lvalue() == (1 - 7^3)*zeta__exact(-3)
True
sage: pAdicWeightSpace(7)(5, DirichletGroup(7, Qp(7)).0^4).Lvalue()
0
sage: pAdicWeightSpace(7)(6, DirichletGroup(7, Qp(7)).0^4).Lvalue()
1 + 2*7 + 7^2 + 3*7^3 + 3*7^5 + 4*7^6 + 2*7^7 + 5*7^8 + 2*7^9 + 3*7^10 + 6*7^11 + 2*7^12 + 3*7^13 + 5*7^14 + 6*7^15 + 5*7^16 + 3*7^17 + 6*7^18 + O(7^19)
"""
if self._k > 0:
return -self._chi.bernoulli(self._k) / self._k
if self.is_trivial():
return Infinity
else:
raise NotImplementedError(
"Don't know how to compute value of this L-function")