I think I found out.
There is an assertion in `tensor_constructor` which is too strict, and
`plethysm` should return an element of the parent, not of the tensor
product. I'll open a ticket.
Martin
"""
sage: S = SymmetricFunctions(QQ)
sage: S.inject_shorthands()
sage: t = tensor([s[1,1], h[2]])
sage: P = TwoPositions(S.s(), S.h())
sage: x = P(t)
sage: 2*x
sage: h[2](x)
"""
def from_ch_characters(t):
P = TwoPositions(*t.parent()._sets)
return P(t)
class TwoPositionsElement(CombinatorialFreeModule_Tensor.Element):
pass
from sage.combinat.free_module import CombinatorialFreeModule_Tensor,
CartesianProductWithFlattening
class TwoPositions(CombinatorialFreeModule_Tensor):
def __init__(self, *modules):
cat = HopfAlgebrasWithBasis(QQ).TensorProducts()
CombinatorialFreeModule_Tensor.__init__(self,
modules,
category = cat)
@cached_method
def tensor_constructor(self, modules):
assert(module in ModulesWithBasis(self.base_ring()) for module in
modules)
# assert(tensor(modules) == self)
# a list l such that l[i] is True if modules[i] is readily a tensor
product
is_tensor = [isinstance(module, CombinatorialFreeModule_Tensor) for
module in modules]
# the tensor_constructor, on basis elements
result = self.monomial * CartesianProductWithFlattening(is_tensor)
#.
# TODO: make this into an element of Hom( A x B, C ) when those
will exist
for i in range(0, len(modules)):
result = modules[i]._module_morphism(result, position = i,
codomain = self)
return result
def __repr__(self):
return "TwoPositions in %s"%(self._sets,)
Element = TwoPositionsElement
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
