Skip to content

Commit

Permalink
Trac #15444: Two algorithms for k-charge do not give same answer
Browse files Browse the repository at this point in the history
Currently, the two implementations of k-charge do not give the same
answer:
{{{
sage: T =
WeakTableaux(4,[4,3,2,1],[2,2,2,2,1,1],representation='bounded')
sage: for t in T:
    print t.k_charge(), t.k_charge(algorithm='J')
....:
9 10
10 10
8 8
9 9
10 10
8 9
11 11
}}}
Comparing against the expansion of Hall-Littlewood symmetric functions
in terms of k-Schur functions, it seems that the I-implementation is
correct
{{{
sage: Sym = SymmetricFunctions(QQ['t'])
sage: Qp = Sym.hall_littlewood().Qp()
sage: ks = Sym.kschur(4)
sage: ks(Qp[2,2,2,2,1,1])[Partition([4,3,2,1])]
t^11 + 2*t^10 + 2*t^9 + 2*t^8
}}}

Compared to the book http://arxiv.org/abs/1301.3569 pg. 84
the bug seems to be in the method _height_of_restricted_subword in
k_tableau.py.

URL: http://trac.sagemath.org/15444
Reported by: aschilling
Ticket author(s): Anne Schilling
Reviewer(s): Mike Zabrocki
  • Loading branch information
Release Manager authored and vbraun committed Jan 3, 2014
2 parents 26cd2c9 + 8df6474 commit 8b85f8d
Showing 1 changed file with 6 additions and 1 deletion.
7 changes: 6 additions & 1 deletion src/sage/combinat/k_tableau.py
Expand Up @@ -1128,6 +1128,10 @@ def k_charge_J(self):
Traceback (most recent call last):
...
ValueError: k-charge is not defined for skew weak tableaux
sage: t = WeakTableau([[1, 1, 2, 3], [2, 4, 4], [3, 6], [5]], 4, representation='bounded')
sage: t.k_charge() == t.k_charge(algorithm = 'J')
True
"""
if self.parent()._skew:
raise ValueError("k-charge is not defined for skew weak tableaux")
Expand Down Expand Up @@ -1182,8 +1186,9 @@ def _height_of_restricted_subword(self, sw, r):
sage: t._height_of_restricted_subword(s,6)
4
"""
R = filter(lambda v : self[v[0]][v[1]] < r, self.shape().to_partition().cells())
L = filter(lambda v: self[v[0]][v[1]] <= r, sw)
return max([v[0] for v in L])
return max([v[0] for v in L+R])

class WeakTableaux_core(WeakTableaux_abstract):
r"""
Expand Down

0 comments on commit 8b85f8d

Please sign in to comment.