def __classcall_private__(cls, cartan_type, la, mu):
"""
Normalize input to ensure a unique representation.
TESTS::
sage: K1 = crystals.KacModule(['A', [2,1]], [2,1], [1])
sage: K2 = crystals.KacModule(CartanType(['A', [2,1]]), (2,1), (1,))
sage: K1 is K2
True
"""
cartan_type = CartanType(cartan_type)
la = _Partitions(la)
mu = _Partitions(mu)
return super(CrystalOfKacModule, cls).__classcall__(cls, cartan_type, la, mu)
def __classcall_private__(cls, cartan_type, la, mu):
"""
Normalize input to ensure a unique representation.
TESTS::
sage: K1 = crystals.KacModule(['A', [2,1]], [2,1], [1])
sage: K2 = crystals.KacModule(CartanType(['A', [2,1]]), (2,1), (1,))
sage: K1 is K2
True
"""
cartan_type = CartanType(cartan_type)
la = _Partitions(la)
mu = _Partitions(mu)
return super(CrystalOfKacModule, cls).__classcall__(cls, cartan_type, la, mu)
def some_elements(self):
r"""
Return some elements of ``self``.
EXAMPLES::
sage: L = lie_algebras.SymplecticDerivation(QQ, 5)
sage: L.some_elements()
[a1*a2, b1*b3, a1*a1*a2, b3*b4, a1*a4*b3,
a1*a2 - 1/2*a1*a2*a2*a5 + a1*a1*a2*b1*b4]
"""
d = self.monomial
g = self._g
return [d( _Partitions([2,1]) ), d( _Partitions([g+3,g+1]) ), d( _Partitions([2,1,1])),
d( _Partitions([2*g-1,2*g-2]) ), d( _Partitions([2*g-2,g-1,1]) ),
self.an_element()]
def _an_element_(self):
r"""
Return an element of ``self``.
EXAMPLES::
sage: L = lie_algebras.SymplecticDerivation(QQ, 5)
sage: L.an_element()
a1*a2 - 1/2*a1*a2*a2*a5 + a1*a1*a2*b1*b4
"""
d = self.monomial
return (
d( _Partitions([2,1]) )
- self.base_ring().an_element() * d( _Partitions([5,2,2,1]) )
+ d( _Partitions([2*self._g-1, self._g+1, 2, 1, 1]) )
)
def spin_polynomial_square(part, weight, length):
r"""
Returns the spin polynomial associated with ``part``, ``weight``, and
``length``, with the substitution `t \to t^2` made.
EXAMPLES::
sage: from sage.combinat.ribbon_tableau import spin_polynomial_square
sage: spin_polynomial_square([6,6,6],[4,2],3)
t^12 + t^10 + 2*t^8 + t^6 + t^4
sage: spin_polynomial_square([6,6,6],[4,1,1],3)
t^12 + 2*t^10 + 3*t^8 + 2*t^6 + t^4
sage: spin_polynomial_square([3,3,3,2,1], [2,2], 3)
t^7 + t^5
sage: spin_polynomial_square([3,3,3,2,1], [2,1,1], 3)
2*t^7 + 2*t^5 + t^3
sage: spin_polynomial_square([3,3,3,2,1], [1,1,1,1], 3)
3*t^7 + 5*t^5 + 3*t^3 + t
sage: spin_polynomial_square([5,4,3,2,1,1,1], [2,2,1], 3)
2*t^9 + 6*t^7 + 2*t^5
sage: spin_polynomial_square([[6]*6, [3,3]], [4,4,2], 3)
3*t^18 + 5*t^16 + 9*t^14 + 6*t^12 + 3*t^10
"""
R = ZZ['t']
if part in _Partitions:
part = SkewPartition([part,_Partitions([])])
elif part in SkewPartitions():
part = SkewPartition(part)
if part == [[],[]] and weight == []:
return R.one()
t = R.gen()
return R(graph_implementation_rec(part, weight, length, functools.partial(spin_rec,t))[0])
def spin_polynomial_square(part, weight, length):
r"""
Returns the spin polynomial associated with ``part``, ``weight``, and
``length``, with the substitution `t \to t^2` made.
EXAMPLES::
sage: from sage.combinat.ribbon_tableau import spin_polynomial_square
sage: spin_polynomial_square([6,6,6],[4,2],3)
t^12 + t^10 + 2*t^8 + t^6 + t^4
sage: spin_polynomial_square([6,6,6],[4,1,1],3)
t^12 + 2*t^10 + 3*t^8 + 2*t^6 + t^4
sage: spin_polynomial_square([3,3,3,2,1], [2,2], 3)
t^7 + t^5
sage: spin_polynomial_square([3,3,3,2,1], [2,1,1], 3)
2*t^7 + 2*t^5 + t^3
sage: spin_polynomial_square([3,3,3,2,1], [1,1,1,1], 3)
3*t^7 + 5*t^5 + 3*t^3 + t
sage: spin_polynomial_square([5,4,3,2,1,1,1], [2,2,1], 3)
2*t^9 + 6*t^7 + 2*t^5
sage: spin_polynomial_square([[6]*6, [3,3]], [4,4,2], 3)
3*t^18 + 5*t^16 + 9*t^14 + 6*t^12 + 3*t^10
"""
R = ZZ['t']
t = R.gen()
if part in _Partitions:
part = SkewPartition([part,_Partitions([])])
elif part in SkewPartitions():
part = SkewPartition(part)
if part == [[],[]] and weight == []:
return t.parent()(1)
return R(graph_implementation_rec(part, weight, length, functools.partial(spin_rec,t))[0])
def bottom_schur_function(self, partition, degree=None):
r"""
Return the least-degree component of ``s[partition]``,
where ``s`` denotes the Schur basis of the symmetric
functions, and the grading is not the usual grading on the
symmetric functions but rather the grading which gives
every `p_i` degree `1`.
This least-degree component has its degree equal to the
Frobenius rank of ``partition``, while the degree with respect
to the usual grading is still the size of ``partition``.
This method requires the base ring to be a (commutative)
`\QQ`-algebra. This restriction is unavoidable, since
the least-degree component (in general) has noninteger
coefficients in all classical bases of the symmetric
functions.
The optional keyword ``degree`` allows taking any
homogeneous component rather than merely the least-degree
one. Specifically, if ``degree`` is set, then the
``degree``-th component will be returned.
REFERENCES:
.. [ClSt03] Peter Clifford, Richard P. Stanley,
*Bottom Schur functions*.
:arxiv:`math/0311382v2`.
EXAMPLES::
sage: Sym = SymmetricFunctions(QQ)
sage: p = Sym.p()
sage: p.bottom_schur_function([2,2,1])
-1/6*p[3, 2] + 1/4*p[4, 1]
sage: p.bottom_schur_function([2,1])
-1/3*p[3]
sage: p.bottom_schur_function([3])
1/3*p[3]
sage: p.bottom_schur_function([1,1,1])
1/3*p[3]
sage: p.bottom_schur_function(Partition([1,1,1]))
1/3*p[3]
sage: p.bottom_schur_function([2,1], degree=1)
-1/3*p[3]
sage: p.bottom_schur_function([2,1], degree=2)
0
sage: p.bottom_schur_function([2,1], degree=3)
1/3*p[1, 1, 1]
sage: p.bottom_schur_function([2,2,1], degree=3)
1/8*p[2, 2, 1] - 1/6*p[3, 1, 1]
"""
from sage.combinat.partition import _Partitions
s = self.realization_of().schur()
partition = _Partitions(partition)
if degree is None:
degree = partition.frobenius_rank()
s_partition = self(s[partition])
return self.sum_of_terms([(p, coeff) for p, coeff in s_partition if len(p) == degree], distinct=True)
def bracket_on_basis(self, x, y):
r"""
Return the bracket of basis elements indexed by ``x`` and ``y``,
where ``i < j``.
EXAMPLES::
sage: L = lie_algebras.SymplecticDerivation(QQ, 5)
sage: L.bracket_on_basis([5,2,1], [5,1,1])
0
sage: L.bracket_on_basis([6,1], [3,1,1])
-2*a1*a1*a3
sage: L.bracket_on_basis([9,2,1], [4,1,1])
-a1*a1*a1*a2
sage: L.bracket_on_basis([5,5,2], [6,1,1])
0
sage: L.bracket_on_basis([5,5,5], [10,3])
3*a3*a5*a5
sage: L.bracket_on_basis([10,10,10], [5,3])
-3*a3*b5*b5
"""
g = self._g
ret = {}
one = self.base_ring().one()
for i,xi in enumerate(x):
for j,yj in enumerate(y):
# The symplectic form will be 0
if (xi <= g and yj <= g) or (xi > g and yj > g):
continue
if xi <= g and yj > g:
if xi != yj - g:
continue
m = _Partitions(sorted(x[:i] + x[i+1:] + y[:j] + y[j+1:], reverse=True))
if m in ret:
ret[m] += one
else:
ret[m] = one
else: # if ci > g and yj <= g:
if xi - g != yj:
continue
m = _Partitions(sorted(x[:i] + x[i+1:] + y[:j] + y[j+1:], reverse=True))
if m in ret:
ret[m] -= one
else:
ret[m] = -one
return self._from_dict(ret, remove_zeros=True)
def compat(n, mu, nu):
r"""
Generate all possible partitions of `n` that can precede `\mu, \nu`
in a rigging sequence.
INPUT:
- ``n`` -- a positive integer
- ``mu``, ``nu`` -- partitions
OUTPUT:
- a list of partitions
EXAMPLES::
sage: from sage.combinat.sf.kfpoly import *
sage: compat(4, [1], [2,1])
[[1, 1, 1, 1], [2, 1, 1], [2, 2], [3, 1], [4]]
sage: compat(3, [1], [2,1])
[[1, 1, 1], [2, 1], [3]]
sage: compat(2, [1], [])
[[2]]
sage: compat(3, [1], [])
[[2, 1], [3]]
sage: compat(3, [2], [1])
[[3]]
sage: compat(4, [1,1], [])
[[2, 2], [3, 1], [4]]
sage: compat(4, [2], [])
[[4]]
"""
l = max(len(mu), len(nu))
mmu = list(mu) + [0] * (l - len(mu))
nnu = list(nu) + [0] * (l - len(nu))
bd = []
sa = 0
for i in range(l):
sa += 2 * mmu[i] - nnu[i]
bd.append(sa)
for la in ZS1_iterator(n):
if dom(la, bd):
return [
x.conjugate() for x in _Partitions(la).dominated_partitions()
]
return [] # _Partitions([])
def compat(n, mu, nu):
r"""
Generate all possible partitions of `n` that can precede `\mu, \nu`
in a rigging sequence.
INPUT:
- ``n`` -- a positive integer
- ``mu``, ``nu`` -- partitions
OUTPUT:
- a list of partitions
EXAMPLES::
sage: from sage.combinat.sf.kfpoly import *
sage: compat(4, [1], [2,1])
[[1, 1, 1, 1], [2, 1, 1], [2, 2], [3, 1], [4]]
sage: compat(3, [1], [2,1])
[[1, 1, 1], [2, 1], [3]]
sage: compat(2, [1], [])
[[2]]
sage: compat(3, [1], [])
[[2, 1], [3]]
sage: compat(3, [2], [1])
[[3]]
sage: compat(4, [1,1], [])
[[2, 2], [3, 1], [4]]
sage: compat(4, [2], [])
[[4]]
"""
l = max(len(mu), len(nu))
mmu = list(mu) + [0]*(l-len(mu))
nnu = list(nu) + [0]*(l-len(nu))
bd = []
sa = 0
for i in range(l):
sa += 2*mmu[i] - nnu[i]
bd.append(sa)
for la in ZS1_iterator(n):
if dom(la, bd):
return [x.conjugate() for x in _Partitions(la).dominated_partitions()]
return [] # _Partitions([])
def kfpoly(mu, nu, t=None):
r"""
Return the Kostka-Foulkes polynomial `K_{\mu, \nu}(t)`
by generating all rigging sequences for the shape `\mu`, and then
selecting those of content `\nu`.
INPUT:
- ``mu``, ``nu`` -- partitions
- ``t`` -- an optional parameter (default: ``None``)
OUTPUT:
- the Koskta-Foulkes polynomial indexed by partitions ``mu`` and ``nu`` and
evaluated at the parameter ``t``. If ``t`` is ``None`` the resulting polynomial
is in the polynomial ring `\ZZ['t']`.
EXAMPLES::
sage: from sage.combinat.sf.kfpoly import kfpoly
sage: kfpoly([2,2], [2,1,1])
t
sage: kfpoly([4], [2,1,1])
t^3
sage: kfpoly([4], [2,2])
t^2
sage: kfpoly([1,1,1,1], [2,2])
0
TESTS::
sage: kfpoly([], [])
1
"""
if mu == nu:
return 1
if t is None:
t = polygen(ZZ, 't')
nuc = _Partitions(nu).conjugate()
f = lambda x: weight(x, t) if x[0] == nuc else 0
return sum(f(rg) for rg in riggings(mu))
def __classcall_private__(cls, ct, shape):
"""
Normalize input to ensure a unique representation.
TESTS::
sage: crystals.Tableaux(['A', [1, 2]], shape=[2,1])
Crystal of BKK tableaux of shape [2, 1] of gl(2|3)
sage: crystals.Tableaux(['A', [1, 1]], shape=[3,3,3])
Traceback (most recent call last):
...
ValueError: invalid hook shape
"""
ct = CartanType(ct)
shape = _Partitions(shape)
if len(shape) > ct.m + 1 and shape[ct.m+1] > ct.n + 1:
raise ValueError("invalid hook shape")
return super(CrystalOfBKKTableaux, cls).__classcall__(cls, ct, shape)
def __classcall_private__(cls, ct, shape):
"""
Normalize input to ensure a unique representation.
TESTS::
sage: crystals.Tableaux(['A', [1, 2]], shape=[2,1])
Crystal of BKK tableaux of shape [2, 1] of gl(2|3)
sage: crystals.Tableaux(['A', [1, 1]], shape=[3,3,3])
Traceback (most recent call last):
...
ValueError: invalid hook shape
"""
ct = CartanType(ct)
shape = _Partitions(shape)
if len(shape) > ct.m + 1 and shape[ct.m + 1] > ct.n + 1:
raise ValueError("invalid hook shape")
return super(CrystalOfBKKTableaux, cls).__classcall__(cls, ct, shape)
def kfpoly(mu, nu, t=None):
r"""
Returns the Kostka-Foulkes polynomial `K_{\mu, \nu}(t)`
by generating all rigging sequences for the shape `\mu`, and then
selecting those of content `\nu`.
INPUT:
- ``mu``, ``nu`` -- partitions
- ``t`` -- an optional parameter (default: ``None``)
OUTPUT:
- the Koskta-Foulkes polynomial indexed by partitions ``mu`` and ``nu`` and
evaluated at the parameter ``t``. If ``t`` is ``None`` the resulting polynomial
is in the polynomial ring `\mathbb{Z}['t']`.
EXAMPLES::
sage: from sage.combinat.sf.kfpoly import kfpoly
sage: kfpoly([2,2], [2,1,1])
t
sage: kfpoly([4], [2,1,1])
t^3
sage: kfpoly([4], [2,2])
t^2
sage: kfpoly([1,1,1,1], [2,2])
0
"""
if mu == nu:
return 1
elif mu == []:
return 0
if t is None:
t = polygen(ZZ, 't')
nuc = _Partitions(nu).conjugate()
f = lambda x: weight(x, t) if x[0] == nuc else 0
res = sum(f(rg) for rg in riggings(mu))
return res
def __classcall_private__(cls, n=None):
r"""
This class returns the appropriate parent based on arguments.
See the documentation for :class:`StandardTableaux` for more
information.
TESTS::
sage: SST = StandardSuperTableaux(); SST
Standard super tableaux
sage: StandardSuperTableaux(3)
Standard super tableaux of size 3
sage: StandardSuperTableaux([2,2])
Standard super tableaux of shape [2, 2]
sage: StandardSuperTableaux(-1)
Traceback (most recent call last):
...
ValueError: the argument must be a non-negative integer or a
partition
sage: StandardSuperTableaux([[1]])
Traceback (most recent call last):
...
ValueError: the argument must be a non-negative integer or a
partition
"""
from sage.combinat.partition import _Partitions
from sage.combinat.skew_partition import SkewPartitions
if n is None:
return StandardSuperTableaux_all()
elif n in _Partitions:
return StandardSuperTableaux_shape(_Partitions(n))
elif n in SkewPartitions():
raise NotImplementedError("standard super tableau for skew "
"partitions is not implemented yet")
if not isinstance(n, (int, Integer)) or n < 0:
raise ValueError("the argument must be a non-negative integer"
" or a partition")
return StandardSuperTableaux_size(n)
def __classcall_private__(cls, shape, weight, length):
"""
Normalize input to ensure a unique representation.
EXAMPLES::
sage: R = RibbonTableaux([[2,1],[]],[1,1,1],1)
sage: R2 = RibbonTableaux(SkewPartition([[2,1],[]]),(1,1,1),1)
sage: R is R2
True
"""
if shape in _Partitions:
shape = _Partitions(shape)
shape = SkewPartition([shape, shape.core(length)])
else:
shape = SkewPartition(shape)
if shape.size() != length*sum(weight):
raise ValueError("Incompatible shape and weight")
return super(RibbonTableaux, cls).__classcall__(cls, shape, tuple(weight), length)
def __classcall_private__(cls, shape, weight, length):
"""
Normalize input to ensure a unique representation.
EXAMPLES::
sage: R = RibbonTableaux([[2,1],[]],[1,1,1],1)
sage: R2 = RibbonTableaux(SkewPartition([[2,1],[]]),(1,1,1),1)
sage: R is R2
True
"""
if shape in _Partitions:
shape = _Partitions(shape)
shape = SkewPartition([shape, shape.core(length)])
else:
shape = SkewPartition(shape)
if shape.size() != length*sum(weight):
raise ValueError("Incompatible shape and weight")
return super(RibbonTableaux, cls).__classcall__(cls, shape, tuple(weight), length)
def module_generator(self, shape):
"""
This yields the module generator (or highest weight element) of a classical
crystal of given shape. The module generator is the unique tableau with equal
shape and content.
EXAMPLES::
sage: T = crystals.Tableaux(['D',3], shape = [1,1])
sage: T.module_generator([1,1])
[[1], [2]]
sage: T = crystals.Tableaux(['D',4],shape=[2,2,2,-2])
sage: T.module_generator(tuple([2,2,2,-2]))
[[1, 1], [2, 2], [3, 3], [-4, -4]]
sage: T.cardinality()
294
sage: T = crystals.Tableaux(['D',4],shape=[2,2,2,2])
sage: T.module_generator(tuple([2,2,2,2]))
[[1, 1], [2, 2], [3, 3], [4, 4]]
sage: T.cardinality()
294
"""
type = self.cartan_type()
if type[0] == 'D' and len(shape) == type[1] and shape[type[1] - 1] < 0:
invert = True
shape = shape[:-1] + (-shape[type[1] - 1], )
else:
invert = False
p = _Partitions(shape).conjugate()
# The column canonical tableau, read by columns
module_generator = flatten([[val - i for i in range(val)]
for val in p])
if invert:
module_generator = [(-x if x == type[1] else x)
for x in module_generator]
return self(list=[self.letters(x) for x in module_generator])
def _supp_to_s(self, gamma):
r"""
This is a helper function that is not meant to be called directly.
Given the support of an element `x_1^{\gamma_1} x_2^{\gamma_2} \cdots
x_\ell^{\gamma_\ell}` in the ``ShiftingOperatorAlgebra``, return
the appropriate `s_\gamma` in the Schur basis using
"Schur function straightening" in [BMPS2018]_ Proposition 4.1.
EXAMPLES::
sage: S = ShiftingOperatorAlgebra(QQ)
sage: s = SymmetricFunctions(QQ).s()
sage: S._supp_to_s(S([3,2,1]).support_of_term())
s[3, 2, 1]
sage: S._supp_to_s(S([2,3,1]).support_of_term())
0
sage: S._supp_to_s(S([2,4,-1,1]).support_of_term())
s[3, 3]
sage: S._supp_to_s(S([3,2,0]).support_of_term())
s[3, 2]
"""
def number_of_noninversions(lis):
return sum(1 for i, val in enumerate(lis)
for j in range(i + 1, len(lis))
if val < lis[j]) # i < j is already enforced
rho = list(range(len(gamma) - 1, -1, -1))
combined = [g + r for g, r in zip(gamma, rho)]
if len(set(combined)) == len(combined) and all(e >= 0
for e in combined):
sign = (-1)**number_of_noninversions(combined)
sort_combined = sorted(combined, reverse=True)
new_gamma = [sc - r for sc, r in zip(sort_combined, rho)]
return sign * self._sym_s(_Partitions(new_gamma))
else:
return self._sym_s.zero()
def _element_constructor_(self, x):
"""
Convert ``x`` into ``self``, if coercion failed.
INPUT:
- ``x`` -- an element of the symmetric functions
EXAMPLES::
sage: s = SymmetricFunctions(QQ).s()
sage: s(2)
2*s[]
sage: s([2,1]) # indirect doctest
s[2, 1]
sage: McdJ = SymmetricFunctions(QQ['q','t'].fraction_field()).macdonald().J()
sage: s = SymmetricFunctions(McdJ.base_ring()).s()
sage: s._element_constructor_(McdJ(s[2,1]))
s[2, 1]
TESTS:
Check that non-Schur bases raise an error when given skew partitions
(:trac:`19218`)::
sage: e = SymmetricFunctions(QQ).e()
sage: e([[2,1],[1]])
Traceback (most recent call last):
...
TypeError: do not know how to make x (= [[2, 1], [1]]) an element of self
"""
R = self.base_ring()
eclass = self.element_class
if isinstance(x, int):
x = Integer(x)
##############
# Partitions #
##############
if x in _Partitions:
return eclass(self, {_Partitions(x): R.one()})
# Todo: discard all of this which is taken care by Sage's coercion
# (up to changes of base ring)
##############
# Dual bases #
##############
elif sfa.is_SymmetricFunction(x) and hasattr(x, 'dual'):
#Check to see if it is the dual of some other basis
#If it is, try to coerce its corresponding element
#in the other basis
return self(x.dual())
##################################################################
# Symmetric Functions, same basis, possibly different coeff ring #
##################################################################
# self.Element is used below to test if another symmetric
# function is expressed in the same basis but in another
# ground ring. This idiom is fragile and depends on the
# internal (unstable) specifications of parents and categories
#
# TODO: find the right idiom
#
# One cannot use anymore self.element_class: it is build by
# the category mechanism, and depends on the coeff ring.
elif isinstance(x, self.Element):
P = x.parent()
#same base ring
if P is self:
return x
#different base ring
else:
return eclass(self, dict([ (e1,R(e2)) for e1,e2 in x._monomial_coefficients.items()]))
##################################################
# Classical Symmetric Functions, different basis #
##################################################
elif isinstance(x, SymmetricFunctionAlgebra_classical.Element):
R = self.base_ring()
xP = x.parent()
xm = x.monomial_coefficients()
#determine the conversion function.
try:
t = conversion_functions[(xP.basis_name(),self.basis_name())]
except AttributeError:
raise TypeError("do not know how to convert from %s to %s"%(xP.basis_name(), self.basis_name()))
if R == QQ and xP.base_ring() == QQ:
if xm:
return self._from_dict(t(xm)._monomial_coefficients, coerce=True)
else:
return self.zero()
else:
f = lambda part: self._from_dict(t( {part: ZZ.one()} )._monomial_coefficients)
return self._apply_module_endomorphism(x, f)
###############################
# Hall-Littlewood Polynomials #
###############################
elif isinstance(x, hall_littlewood.HallLittlewood_generic.Element):
#
#Qp: Convert to Schur basis and then convert to self
#
if isinstance(x, hall_littlewood.HallLittlewood_qp.Element):
Qp = x.parent()
sx = Qp._s._from_cache(x, Qp._s_cache, Qp._self_to_s_cache, t=Qp.t)
return self(sx)
#
#P: Convert to Schur basis and then convert to self
#
elif isinstance(x, hall_littlewood.HallLittlewood_p.Element):
P = x.parent()
sx = P._s._from_cache(x, P._s_cache, P._self_to_s_cache, t=P.t)
return self(sx)
#
#Q: Convert to P basis and then convert to self
#
elif isinstance(x, hall_littlewood.HallLittlewood_q.Element):
return self( x.parent()._P( x ) )
#######
# LLT #
#######
#Convert to m and then to self.
elif isinstance(x, llt.LLT_generic.Element):
P = x.parent()
BR = self.base_ring()
zero = BR.zero()
PBR = P.base_ring()
if not BR.has_coerce_map_from(PBR):
raise TypeError("no coerce map from x's parent's base ring (= %s) to self's base ring (= %s)"%(PBR, self.base_ring()))
z_elt = {}
for m, c in x._monomial_coefficients.iteritems():
n = sum(m)
P._m_cache(n)
for part in P._self_to_m_cache[n][m]:
z_elt[part] = z_elt.get(part, zero) + BR(c*P._self_to_m_cache[n][m][part].subs(t=P.t))
m = P._sym.monomial()
return self( m._from_dict(z_elt) )
#########################
# Macdonald Polynomials #
#########################
elif isinstance(x, macdonald.MacdonaldPolynomials_generic.Element):
if isinstance(x, macdonald.MacdonaldPolynomials_j.Element):
J = x.parent()
sx = J._s._from_cache(x, J._s_cache, J._self_to_s_cache, q=J.q, t=J.t)
return self(sx)
elif isinstance(x, (macdonald.MacdonaldPolynomials_q.Element, macdonald.MacdonaldPolynomials_p.Element)):
J = x.parent()._J
jx = J(x)
sx = J._s._from_cache(jx, J._s_cache, J._self_to_s_cache, q=J.q, t=J.t)
return self(sx)
elif isinstance(x, (macdonald.MacdonaldPolynomials_h.Element,macdonald.MacdonaldPolynomials_ht.Element)):
H = x.parent()
sx = H._self_to_s(x)
return self(sx)
elif isinstance(x, macdonald.MacdonaldPolynomials_s.Element):
S = x.parent()
sx = S._s._from_cache(x, S._s_cache, S._self_to_s_cache, q=S.q, t=S.t)
return self(sx)
else:
raise TypeError
####################
# Jack Polynomials #
####################
elif isinstance(x, jack.JackPolynomials_generic.Element):
if isinstance(x, jack.JackPolynomials_p.Element):
P = x.parent()
mx = P._m._from_cache(x, P._m_cache, P._self_to_m_cache, t=P.t)
return self(mx)
if isinstance(x, (jack.JackPolynomials_j.Element, jack.JackPolynomials_q.Element)):
return self( x.parent()._P(x) )
else:
raise TypeError
####################################################
# Bases defined by orthogonality and triangularity #
####################################################
elif isinstance(x, orthotriang.SymmetricFunctionAlgebra_orthotriang.Element):
#Convert to its base and then to self
xp = x.parent()
if self is xp._sf_base:
return xp._sf_base._from_cache(x, xp._base_cache, xp._self_to_base_cache)
else:
return self( xp._sf_base(x) )
#################################
# Last shot -- try calling R(x) #
#################################
else:
try:
return eclass(self, {_Partitions([]): R(x)})
except Exception:
raise TypeError("do not know how to make x (= {}) an element of self".format(x))
def __classcall_private__(cls, cartan_type, shapes=None, shape=None):
"""
Normalizes the input arguments to ensure unique representation,
and to delegate the construction of spin tableaux.
EXAMPLES::
sage: T1 = crystals.Tableaux(CartanType(['A',3]), shape = [2,2])
sage: T2 = crystals.Tableaux(['A',3], shape = (2,2))
sage: T3 = crystals.Tableaux(['A',3], shapes = ([2,2],))
sage: T2 is T1, T3 is T1
(True, True)
sage: T1 = crystals.Tableaux(['A', [1,1]], shape=[3,1,1,1])
sage: T1
Crystal of BKK tableaux of shape [3, 1, 1, 1] of gl(2|2)
sage: T2 = crystals.Tableaux(['A', [1,1]], [3,1,1,1])
sage: T1 is T2
True
"""
cartan_type = CartanType(cartan_type)
if cartan_type.letter == 'A' and isinstance(cartan_type,
SuperCartanType_standard):
if shape is None:
shape = shapes
shape = _Partitions(shape)
from sage.combinat.crystals.bkk_crystals import CrystalOfBKKTableaux
return CrystalOfBKKTableaux(cartan_type, shape=shape)
if cartan_type.letter == 'Q':
if any(shape[i] == shape[i + 1] for i in range(len(shape) - 1)):
raise ValueError("not a strict partition")
shape = _Partitions(shape)
return CrystalOfQueerTableaux(cartan_type, shape=shape)
n = cartan_type.rank()
# standardize shape/shapes input into a tuple of tuples
# of length n, or n+1 in type A
assert operator.xor(shape is not None, shapes is not None)
if shape is not None:
shapes = (shape, )
if cartan_type.type() == "A":
n1 = n + 1
else:
n1 = n
if not all(all(i == 0 for i in shape[n1:]) for shape in shapes):
raise ValueError(
"shapes should all have length at most equal to the rank or the rank + 1 in type A"
)
spin_shapes = tuple((tuple(shape) + (0, ) * (n1 - len(shape)))[:n1]
for shape in shapes)
try:
shapes = tuple(
tuple(trunc(i) for i in shape) for shape in spin_shapes)
except Exception:
raise ValueError(
"shapes should all be partitions or half-integer partitions")
if spin_shapes == shapes:
shapes = tuple(
_Partitions(shape) if shape[n1 - 1] in NN else shape
for shape in shapes)
return super(CrystalOfTableaux,
cls).__classcall__(cls, cartan_type, shapes)
# Handle the construction of a crystals of spin tableaux
# Caveat: this currently only supports all shapes being half
# integer partitions of length the rank for type B and D. In
# particular, for type D, the spins all have to be plus or all
# minus spins
if any(len(sh) != n for sh in shapes):
raise ValueError(
"the length of all half-integer partition shapes should be the rank"
)
if any(2 * i % 2 != 1 for shape in spin_shapes for i in shape):
raise ValueError(
"shapes should be either all partitions or all half-integer partitions"
)
if any(
any(i < j
for i, j in zip(shape, shape[1:-1] + (abs(shape[-1]), )))
for shape in spin_shapes):
raise ValueError("entries of each shape must be weakly decreasing")
if cartan_type.type() == 'D':
if all(i >= 0 for shape in spin_shapes for i in shape):
S = CrystalOfSpinsPlus(cartan_type)
elif all(shape[-1] < 0 for shape in spin_shapes):
S = CrystalOfSpinsMinus(cartan_type)
else:
raise ValueError(
"in type D spins should all be positive or negative")
else:
if any(i < 0 for shape in spin_shapes for i in shape):
raise ValueError("shapes should all be partitions")
S = CrystalOfSpins(cartan_type)
B = CrystalOfTableaux(cartan_type, shapes=shapes)
T = TensorProductOfCrystals(S,
B,
generators=[[S.module_generators[0], x]
for x in B.module_generators])
T.rename("The crystal of tableaux of type %s and shape(s) %s" %
(cartan_type, list(list(shape) for shape in spin_shapes)))
T.shapes = spin_shapes
return T
def bottom_schur_function(self, partition, degree=None):
r"""
Return the least-degree component of ``s[partition]``,
where ``s`` denotes the Schur basis of the symmetric
functions, and the grading is not the usual grading on the
symmetric functions but rather the grading which gives
every `p_i` degree `1`.
This least-degree component has its degree equal to the
Frobenius rank of ``partition``, while the degree with respect
to the usual grading is still the size of ``partition``.
This method requires the base ring to be a (commutative)
`\QQ`-algebra. This restriction is unavoidable, since
the least-degree component (in general) has noninteger
coefficients in all classical bases of the symmetric
functions.
The optional keyword ``degree`` allows taking any
homogeneous component rather than merely the least-degree
one. Specifically, if ``degree`` is set, then the
``degree``-th component will be returned.
REFERENCES:
.. [ClSt03] Peter Clifford, Richard P. Stanley,
*Bottom Schur functions*.
:arxiv:`math/0311382v2`.
EXAMPLES::
sage: Sym = SymmetricFunctions(QQ)
sage: p = Sym.p()
sage: p.bottom_schur_function([2,2,1])
-1/6*p[3, 2] + 1/4*p[4, 1]
sage: p.bottom_schur_function([2,1])
-1/3*p[3]
sage: p.bottom_schur_function([3])
1/3*p[3]
sage: p.bottom_schur_function([1,1,1])
1/3*p[3]
sage: p.bottom_schur_function(Partition([1,1,1]))
1/3*p[3]
sage: p.bottom_schur_function([2,1], degree=1)
-1/3*p[3]
sage: p.bottom_schur_function([2,1], degree=2)
0
sage: p.bottom_schur_function([2,1], degree=3)
1/3*p[1, 1, 1]
sage: p.bottom_schur_function([2,2,1], degree=3)
1/8*p[2, 2, 1] - 1/6*p[3, 1, 1]
"""
from sage.combinat.partition import _Partitions
s = self.realization_of().schur()
partition = _Partitions(partition)
if degree is None:
degree = partition.frobenius_rank()
s_partition = self(s[partition])
return self.sum_of_terms(
[(p, coeff) for p, coeff in s_partition if len(p) == degree],
distinct=True)
def P(i):
return _Partitions([i]) if i else _Partitions([])
def _element_constructor_(self, x):
"""
Convert ``x`` into ``self``, if coercion failed.
INPUT:
- ``x`` -- an element of the symmetric functions
EXAMPLES::
sage: s = SymmetricFunctions(QQ).s()
sage: s(2)
2*s[]
sage: s([2,1]) # indirect doctest
s[2, 1]
sage: McdJ = SymmetricFunctions(QQ['q','t'].fraction_field()).macdonald().J()
sage: s = SymmetricFunctions(McdJ.base_ring()).s()
sage: s._element_constructor_(McdJ(s[2,1]))
s[2, 1]
TESTS:
Check that non-Schur bases raise an error when given skew partitions
(:trac:`19218`)::
sage: e = SymmetricFunctions(QQ).e()
sage: e([[2,1],[1]])
Traceback (most recent call last):
...
TypeError: do not know how to make x (= [[2, 1], [1]]) an element of self
"""
R = self.base_ring()
eclass = self.element_class
if isinstance(x, int):
x = Integer(x)
##############
# Partitions #
##############
if x in _Partitions:
return eclass(self, {_Partitions(x): R.one()})
# Todo: discard all of this which is taken care by Sage's coercion
# (up to changes of base ring)
##############
# Dual bases #
##############
elif sfa.is_SymmetricFunction(x) and hasattr(x, 'dual'):
#Check to see if it is the dual of some other basis
#If it is, try to coerce its corresponding element
#in the other basis
return self(x.dual())
##################################################################
# Symmetric Functions, same basis, possibly different coeff ring #
##################################################################
# self.Element is used below to test if another symmetric
# function is expressed in the same basis but in another
# ground ring. This idiom is fragile and depends on the
# internal (unstable) specifications of parents and categories
#
# TODO: find the right idiom
#
# One cannot use anymore self.element_class: it is build by
# the category mechanism, and depends on the coeff ring.
elif isinstance(x, self.Element):
P = x.parent()
#same base ring
if P is self:
return x
#different base ring
else:
return eclass(
self,
dict([(e1, R(e2))
for e1, e2 in x._monomial_coefficients.items()]))
##################################################
# Classical Symmetric Functions, different basis #
##################################################
elif isinstance(x, SymmetricFunctionAlgebra_classical.Element):
R = self.base_ring()
xP = x.parent()
xm = x.monomial_coefficients()
#determine the conversion function.
try:
t = conversion_functions[(xP.basis_name(), self.basis_name())]
except AttributeError:
raise TypeError("do not know how to convert from %s to %s" %
(xP.basis_name(), self.basis_name()))
if R == QQ and xP.base_ring() == QQ:
if xm:
return self._from_dict(t(xm)._monomial_coefficients,
coerce=True)
else:
return self.zero()
else:
f = lambda part: self._from_dict(
t({
part: ZZ.one()
})._monomial_coefficients)
return self._apply_module_endomorphism(x, f)
###############################
# Hall-Littlewood Polynomials #
###############################
elif isinstance(x, hall_littlewood.HallLittlewood_generic.Element):
#
#Qp: Convert to Schur basis and then convert to self
#
if isinstance(x, hall_littlewood.HallLittlewood_qp.Element):
Qp = x.parent()
sx = Qp._s._from_cache(x,
Qp._s_cache,
Qp._self_to_s_cache,
t=Qp.t)
return self(sx)
#
#P: Convert to Schur basis and then convert to self
#
elif isinstance(x, hall_littlewood.HallLittlewood_p.Element):
P = x.parent()
sx = P._s._from_cache(x, P._s_cache, P._self_to_s_cache, t=P.t)
return self(sx)
#
#Q: Convert to P basis and then convert to self
#
elif isinstance(x, hall_littlewood.HallLittlewood_q.Element):
return self(x.parent()._P(x))
#######
# LLT #
#######
#Convert to m and then to self.
elif isinstance(x, llt.LLT_generic.Element):
P = x.parent()
BR = self.base_ring()
zero = BR.zero()
PBR = P.base_ring()
if not BR.has_coerce_map_from(PBR):
raise TypeError(
"no coerce map from x's parent's base ring (= %s) to self's base ring (= %s)"
% (PBR, self.base_ring()))
z_elt = {}
for m, c in x._monomial_coefficients.iteritems():
n = sum(m)
P._m_cache(n)
for part in P._self_to_m_cache[n][m]:
z_elt[part] = z_elt.get(part, zero) + BR(
c * P._self_to_m_cache[n][m][part].subs(t=P.t))
m = P._sym.monomial()
return self(m._from_dict(z_elt))
#########################
# Macdonald Polynomials #
#########################
elif isinstance(x, macdonald.MacdonaldPolynomials_generic.Element):
if isinstance(x, macdonald.MacdonaldPolynomials_j.Element):
J = x.parent()
sx = J._s._from_cache(x,
J._s_cache,
J._self_to_s_cache,
q=J.q,
t=J.t)
return self(sx)
elif isinstance(x, (macdonald.MacdonaldPolynomials_q.Element,
macdonald.MacdonaldPolynomials_p.Element)):
J = x.parent()._J
jx = J(x)
sx = J._s._from_cache(jx,
J._s_cache,
J._self_to_s_cache,
q=J.q,
t=J.t)
return self(sx)
elif isinstance(x, (macdonald.MacdonaldPolynomials_h.Element,
macdonald.MacdonaldPolynomials_ht.Element)):
H = x.parent()
sx = H._self_to_s(x)
return self(sx)
elif isinstance(x, macdonald.MacdonaldPolynomials_s.Element):
S = x.parent()
sx = S._s._from_cache(x,
S._s_cache,
S._self_to_s_cache,
q=S.q,
t=S.t)
return self(sx)
else:
raise TypeError
####################
# Jack Polynomials #
####################
elif isinstance(x, jack.JackPolynomials_generic.Element):
if isinstance(x, jack.JackPolynomials_p.Element):
P = x.parent()
mx = P._m._from_cache(x, P._m_cache, P._self_to_m_cache, t=P.t)
return self(mx)
if isinstance(x, (jack.JackPolynomials_j.Element,
jack.JackPolynomials_q.Element)):
return self(x.parent()._P(x))
else:
raise TypeError
####################################################
# Bases defined by orthogonality and triangularity #
####################################################
elif isinstance(
x, orthotriang.SymmetricFunctionAlgebra_orthotriang.Element):
#Convert to its base and then to self
xp = x.parent()
if self is xp._sf_base:
return xp._sf_base._from_cache(x, xp._base_cache,
xp._self_to_base_cache)
else:
return self(xp._sf_base(x))
#################################
# Last shot -- try calling R(x) #
#################################
else:
try:
return eclass(self, {_Partitions([]): R(x)})
except Exception:
raise TypeError(
"do not know how to make x (= {}) an element of self".
format(x))
def q_subgroups_of_abelian_group(la, mu, q=None, algorithm='birkhoff'):
r"""
Return the `q`-number of subgroups of type ``mu`` in a finite abelian
group of type ``la``.
INPUT:
- ``la`` -- type of the ambient group as a :class:`Partition`
- ``mu`` -- type of the subgroup as a :class:`Partition`
- ``q`` -- (default: ``None``) an indeterminate or a prime number; if
``None``, this defaults to `q \in \ZZ[q]`
- ``algorithm`` -- (default: ``'birkhoff'``) the algorithm to use can be
one of the following:
- ``'birkhoff`` -- use the Birkhoff formula from [Bu87]_
- ``'delsarte'`` -- use the formula from [Delsarte48]_
OUTPUT:
The number of subgroups of type ``mu`` in a group of type ``la`` as a
polynomial in ``q``.
ALGORITHM:
Let `q` be a prime number and `\lambda = (\lambda_1, \ldots, \lambda_l)`
be a partition. A finite abelian `q`-group is of type `\lambda` if it
is isomorphic to
.. MATH::
\ZZ / q^{\lambda_1} \ZZ \times \cdots \times \ZZ / q^{\lambda_l} \ZZ.
The formula from [Bu87]_ works as follows:
Let `\lambda` and `\mu` be partitions. Let `\lambda^{\prime}` and
`\mu^{\prime}` denote the conjugate partitions to `\lambda` and `\mu`,
respectively. The number of subgroups of type `\mu` in a group of type
`\lambda` is given by
.. MATH::
\prod_{i=1}^{\mu_1} q^{\mu^{\prime}_{i+1}
(\lambda^{\prime}_i - \mu^{\prime}_i)}
\binom{\lambda^{\prime}_i - \mu^{\prime}_{i+1}}
{\mu^{\prime}_i - \mu^{\prime}_{i+1}}_q
The formula from [Delsarte48]_ works as follows:
Let `\lambda` and `\mu` be partitions. Let `(s_1, s_2, \ldots, s_l)`
and `(r_1, r_2, \ldots, r_k)` denote the parts of the partitions
conjugate to `\lambda` and `\mu` respectively. Let
.. MATH::
\mathfrak{F}(\xi_1, \ldots, \xi_k) = \xi_1^{r_2} \xi_2^{r_3} \cdots
\xi_{k-1}^{r_k} \prod_{i_1=r_2}^{r_1-1} (\xi_1-q^{i_1})
\prod_{i_2=r_3}^{r_2-1} (\xi_2-q^{i_2}) \cdots
\prod_{i_k=0}^{r_k-1} (\xi_k-q^{-i_k}).
Then the number of subgroups of type `\mu` in a group of type `\lambda`
is given by
.. MATH::
\frac{\mathfrak{F}(q^{s_1}, q^{s_2}, \ldots, q^{s_k})}{\mathfrak{F}
(q^{r_1}, q^{r_2}, \ldots, q^{r_k})}.
EXAMPLES::
sage: from sage.combinat.q_analogues import q_subgroups_of_abelian_group
sage: q_subgroups_of_abelian_group([1,1], [1])
q + 1
sage: q_subgroups_of_abelian_group([3,3,2,1], [2,1])
q^6 + 2*q^5 + 3*q^4 + 2*q^3 + q^2
sage: R.<t> = QQ[]
sage: q_subgroups_of_abelian_group([5,3,1], [3,1], t)
t^4 + 2*t^3 + t^2
sage: q_subgroups_of_abelian_group([5,3,1], [3,1], 3)
144
sage: q_subgroups_of_abelian_group([1,1,1], [1]) == q_subgroups_of_abelian_group([1,1,1], [1,1])
True
sage: q_subgroups_of_abelian_group([5], [3])
1
sage: q_subgroups_of_abelian_group([1], [2])
0
sage: q_subgroups_of_abelian_group([2], [1,1])
0
TESTS:
Check the same examples with ``algorithm='delsarte'``::
sage: q_subgroups_of_abelian_group([1,1], [1], algorithm='delsarte')
q + 1
sage: q_subgroups_of_abelian_group([3,3,2,1], [2,1], algorithm='delsarte')
q^6 + 2*q^5 + 3*q^4 + 2*q^3 + q^2
sage: q_subgroups_of_abelian_group([5,3,1], [3,1], t, algorithm='delsarte')
t^4 + 2*t^3 + t^2
sage: q_subgroups_of_abelian_group([5,3,1], [3,1], 3, algorithm='delsarte')
144
sage: q_subgroups_of_abelian_group([1,1,1], [1], algorithm='delsarte') == q_subgroups_of_abelian_group([1,1,1], [1,1])
True
sage: q_subgroups_of_abelian_group([5], [3], algorithm='delsarte')
1
sage: q_subgroups_of_abelian_group([1], [2], algorithm='delsarte')
0
sage: q_subgroups_of_abelian_group([2], [1,1], algorithm='delsarte')
0
Check that :trac:`25715` is fixed::
sage: parent(q_subgroups_of_abelian_group([2], [1], algorithm='delsarte'))
Univariate Polynomial Ring in q over Integer Ring
sage: q_subgroups_of_abelian_group([7,7,1], [])
1
sage: q_subgroups_of_abelian_group([7,7,1], [0,0])
1
REFERENCES:
.. [Bu87] Butler, Lynne M. *A unimodality result in the enumeration
of subgroups of a finite abelian group.* Proceedings of the American
Mathematical Society 101, no. 4 (1987): 771-775.
:doi:`10.1090/S0002-9939-1987-0911049-8`
.. [Delsarte48] \S. Delsarte, *Fonctions de Möbius Sur Les Groupes Abeliens
Finis*, Annals of Mathematics, second series, Vol. 45, No. 3, (Jul 1948),
pp. 600-609. http://www.jstor.org/stable/1969047
AUTHORS:
- Amritanshu Prasad (2013-06-07): Implemented the Delsarte algorithm
- Tomer Bauer (2013, 2018): Implemented the Birkhoff algorithm and refactoring
"""
if q is None:
q = ZZ['q'].gen()
la_c = _Partitions(la).conjugate()
mu_c = _Partitions(mu).conjugate()
k = mu_c.length()
if not mu_c:
# There is only one trivial subgroup
return parent(q)(1)
if not la_c.contains(mu_c):
return parent(q)(0)
if algorithm == 'delsarte':
def F(args):
prd = lambda j: prod(args[j] - q**i
for i in range(mu_c[j + 1], mu_c[j]))
F1 = prod(args[i]**mu_c[i + 1] * prd(i) for i in range(k - 1))
return F1 * prod(args[k - 1] - q**i for i in range(mu_c[k - 1]))
return F([q**ss for ss in la_c[:k]]) // F([q**rr for rr in mu_c])
if algorithm == 'birkhoff':
fac1 = q**(sum(mu_c[i + 1] * (la_c[i] - mu_c[i])
for i in range(k - 1)))
fac2 = prod(
q_binomial(la_c[i] - mu_c[i + 1], mu_c[i] - mu_c[i + 1], q=q)
for i in range(k - 1))
fac3 = q_binomial(la_c[k - 1], mu_c[k - 1], q=q)
return prod([fac1, fac2, fac3])
raise ValueError("invalid algorithm choice")
REFERENCES:
- :wikipedia:`Q-Pochhammer_symbol`
"""
if q is None:
q = ZZ['q'].gen()
if n not in ZZ:
raise ValueError("{} must be an integer".format(n))
R = parent(q)
one = R(1)
if n < 0:
return R.prod(one / (one - a / q**-k) for k in range(1, -n + 1))
return R.prod((one - a * q**k) for k in range(n))
@cached_function(key=lambda t, q: (_Partitions(t), q))
def q_jordan(t, q=None):
r"""
Return the `q`-Jordan number of `t`.
If `q` is the power of a prime number, the output is the number of
complete flags in `\GF{q}^N` (where `N` is the size of `t`) stable
under a linear nilpotent endomorphism `f_t` whose Jordan type is
given by `t`, i.e. such that for all `i`:
.. MATH::
\dim (\ker f_t^i) = t[0] + \cdots + t[i-1]
If `q` is unspecified, then it defaults to using the generator `q` for
a univariate polynomial ring over the integers.
def P(i): return _Partitions([i]) if i else _Partitions([]) T = self.tensor_square()
def rectify(self, inner=None, verbose=False):
"""
Rectify ``self``.
This gives the usual rectification of a skew standard tableau and gives a
generalisation to skew semistandard tableaux. The usual construction uses
jeu-de-taquin but here we use the Bender-Knuth involutions.
EXAMPLES::
sage: st = SkewTableau([[None, None, None, 4],[None,None,1,6],[None,None,5],[2,3]])
sage: path_tableaux.SemistandardPathTableau(st).rectify()
[(), (1,), (1, 1), (2, 1, 0), (3, 1, 0, 0), (3, 2, 0, 0, 0), (4, 2, 0, 0, 0, 0)]
sage: path_tableaux.SemistandardPathTableau(st).rectify(verbose=True)
[[(3, 2, 2), (3, 3, 2, 0), (3, 3, 2, 1, 0), (3, 3, 2, 2, 0, 0), (4, 3, 2, 2, 0, 0, 0), (4, 3, 3, 2, 0, 0, 0, 0), (4, 4, 3, 2, 0, 0, 0, 0, 0)],
[(3, 2), (3, 3, 0), (3, 3, 1, 0), (3, 3, 2, 0, 0), (4, 3, 2, 0, 0, 0), (4, 3, 3, 0, 0, 0, 0), (4, 4, 3, 0, 0, 0, 0, 0)],
[(3,), (3, 1), (3, 1, 1), (3, 2, 1, 0), (4, 2, 1, 0, 0), (4, 3, 1, 0, 0, 0), (4, 4, 1, 0, 0, 0, 0)],
[(), (1,), (1, 1), (2, 1, 0), (3, 1, 0, 0), (3, 2, 0, 0, 0), (4, 2, 0, 0, 0, 0)]]
TESTS::
sage: S = SemistandardSkewTableaux([[5,3,3],[3,1]],[3,2,2])
sage: LHS = [path_tableaux.SemistandardPathTableau(st.rectify()) for st in S]
sage: RHS = [path_tableaux.SemistandardPathTableau(st).rectify() for st in S]
sage: LHS == RHS
True
sage: st = SkewTableau([[None, None, None, 4],[None,None,1,6],[None,None,5],[2,3]])
sage: pt = path_tableaux.SemistandardPathTableau(st)
sage: SP = [path_tableaux.SemistandardPathTableau(it) for it in StandardTableaux([3,2,2])]
sage: len(set(pt.rectify(inner=ip) for ip in SP))
1
"""
if not self.is_skew():
return self
n = len(self)
pp = self[0]
P = self.parent()
if inner is None:
initial = [pp[:r] for r in range(len(pp))]
elif _Partitions(inner[-1]) == _Partitions(pp):
initial = list(inner)[:-1]
else:
raise ValueError(
f"the final shape{inner[-1]} must agree with the initial shape {pp}"
)
r = len(initial)
path = P.element_class(P, initial + list(self))
if verbose:
rect = [self]
for i in range(r):
for j in range(n - 1):
path = path.local_rule(r + j - i)
if verbose:
rect.append(
P.element_class(P,
list(path)[r - i - 1:r + n - i - 1]))
if verbose:
return rect
else:
return P.element_class(P, list(path)[:n])
def P(i): return _Partitions([i]) if i else _Partitions([]) T = self.tensor_square()
