On Thu, Mar 29, 2012 at 09:04:41PM -0400, msh...@math.vt.edu wrote:
Is the following a decent way to determine whether element is an element
of a Weyl group of a given Cartan type?
hasattr(element, domain) and hasattr(element.domain(), cartan_type)
and element.domain().cartan_type() ==
On Thu, Mar 29, 2012 at 07:50:31PM -0400, msh...@math.vt.edu wrote:
I need to call the Coxeter group method something different
like reflection_inversions (and the solution becomes trivial)
alternative name: inversions_as_reflections
or someone needs to tell me how to tell python not to run
Ah, shoot; I had forgotten but there is currently a shortcoming with
cached methods which make them rather incompatible with super calls
in subclasses:
class A(object):
@cached_method
def f(self): print I am A.f
class B(A):
def f(self):
super(B,
Hi Marc,
On Sat, Mar 24, 2012 at 08:52:04PM -0400, msh...@math.vt.edu wrote:
Now you should get
sage: W=WeylGroup(['A',2])
sage: w=W.from_reduced_word([1,2,1])
sage: w.inversions()
[alpha[1], alpha[1] + alpha[2], alpha[2]]
Sorry for the slow answer. Here W is a Weyl group
On Sat, Mar 24, 2012 at 08:52:04PM -0400, msh...@math.vt.edu wrote:
Now you should get
sage: W=WeylGroup(['A',2])
sage: w=W.from_reduced_word([1,2,1])
sage: w.inversions()
[alpha[1], alpha[1] + alpha[2], alpha[2]]
Sorry for the slow answer. Here W is a Weyl group implemented as a
group
Anne,
Is there now a simple way to convert
a vector in the ambient space to the root basis?
Longish answer:
The domain of the Weyl group, the space on which it is defined to act,
can be at least one of the following:
1. Ambient space
2. Root lattice
3. Coroot lattice
4. Weight lattice
5.
Frederic,
I pushed a patch (coxeter_ms.patch) to the sage-combinat server.
Now you should get
sage: W=WeylGroup(['A',2])
sage: w=W.from_reduced_word([1,2,1])
sage: w.inversions()
[alpha[1], alpha[1] + alpha[2], alpha[2]]
which is much nicer.
--Mark
Jean Michel wrote:
The
In other words, something like this:
sage: w.inversions()
[alpha[1], alpha[1] + alpha[2], alpha[2]]
sage: w.inversions(reflections=True)
[s1,s1*s2*s1,s2]
+1
what was again the point of having a list rather than a set?
Christian
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Hi all,
Jean Michel wrote:
The list of inversions, in my view, should preferably be a list
of reflections (which does not need the existence of roots and makes
sense for abstract Coxeter groups).
Indeed, in trac_12774-coxeter-ms.patch, there is already a Coxeter group
element
Indeed, in trac_12774-coxeter-ms.patch, there is already a Coxeter group
element method which returns inversions in reflection form:
sage: W = WeylGroup(['A',2],prefix=s)
sage: w = W.from_reduced_word([1,2,1])
sage: w.length_decreasing_reflections_right()
[s1, s1*s2*s1, s2]
If everyone
Christian,
Since WeylGroups has CoxeterGroups as a super category, to me it seems
be perfectly reasonable to name both methods inversions, The one
from WeylGroups then overwrite the one from CoxeterGroups (or does it
happen to be the other way round, Nicolas?). To avoid confusion, maybe
On Thu, Mar 29, 2012 at 09:03:59PM +0200, Christian Stump wrote:
Since WeylGroups has CoxeterGroups as a super category, to me it seems
be perfectly reasonable to name both methods inversions, The one
from WeylGroups then overwrite the one from CoxeterGroups
Indeed.
As for usual inheritance,
Hi Mark,
If I understand correctly, you can you getattr, see
getattr(object, name[, default]) - value
Get a named attribute from an object; getattr(x, 'y') is equivalent to
x.y. When a default argument is given, it is returned when the
attribute doesn't exist; without it, an
Arrgh, my previous question obviously didn't make sense.
I need to call the Coxeter group method something different
like reflection_inversions (and the solution becomes trivial)
or someone needs to tell me how to tell python not to run over
the Coxeter group method (so the method is actually
Christian and Nicolas,
Is the following a decent way to determine whether element is an element
of a Weyl group of a given Cartan type?
hasattr(element, domain) and hasattr(element.domain(), cartan_type)
and element.domain().cartan_type() == cartan_type
E.g. is this likely to change or are
Christian and Nicolas,
I pushed trac_12774-coxeter-ms.patch.
I moved it way up the queue and
had no problems applying the rest of the queue.
I temporarily broke some rules for putting the patch that high on the queue.
E.g., I have a trac ticket but haven't put a version of the patch
on trac just
Hello,
Trying to use inversions for elements of Weyl groups, I found that it
exists, but does not work, and is badly documented and tested. In which
patch is this located ?
Frederic
sage: W=WeylGroup(['A',3])
sage: w=W.from_reduced_word([1,2,1])
sage: w.inversions()
AttributeError:
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