#2808: [with patch, positive review] G2 fundamental weights were the negative of
what they should be.
---------------------------------+------------------------
Reporter: bump | Owner: bump
Type: defect | Status: closed
Priority: major | Milestone: sage-3.0
Component: combinatorics | Resolution: fixed
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
---------------------------------+------------------------
Changes (by chapoton):
* upstream: => N/A
Old description:
> In combinat/root_system.py, the fundamental weights for the various root
> systems are entered by hand. For G2, the fundamental weights were the
> negatives of what they should be.
> {{{
>
> diff -r 80b506b8e07c sage/combinat/root_system.py
> --- a/sage/combinat/root_system.py Tue Apr 01 19:18:55 2008 -0700
> +++ b/sage/combinat/root_system.py Sat Apr 05 08:40:46 2008 -0700
> @@ -788,11 +788,11 @@ class AmbientLattice_g(AmbientLattice_ge
> """
> EXAMPLES:
> sage:
> CartanType(['G',2]).root_system().ambient_lattice().fundamental_weights()
> - [(-1, 0, 1), (-2, 1, 1)]
> + [(1, 0, -1), (2, -1, -1)]
> """
> return [ c0*self._term(0)+c1*self._term(1)+c2*self._term(2) \
> for [c0,c1,c2] in
> - [[-1,0,1],[-2,1,1]]]
> + [[1,0,-1],[2,-1,-1]]]
>
> def WeylDim(type, coeffs):
>
> }}}
New description:
In combinat/root_system.py, the fundamental weights for the various root
systems are entered by hand. For G2, the fundamental weights were the
negatives of what they should be.
{{{
diff -r 80b506b8e07c sage/combinat/root_system.py
--- a/sage/combinat/root_system.py Tue Apr 01 19:18:55 2008 -0700
+++ b/sage/combinat/root_system.py Sat Apr 05 08:40:46 2008 -0700
@@ -788,11 +788,11 @@ class AmbientLattice_g(AmbientLattice_ge
"""
EXAMPLES:
sage:
CartanType(['G',2]).root_system().ambient_lattice().fundamental_weights()
- [(-1, 0, 1), (-2, 1, 1)]
+ [(1, 0, -1), (2, -1, -1)]
"""
return [ c0*self._term(0)+c1*self._term(1)+c2*self._term(2) \
for [c0,c1,c2] in
- [[-1,0,1],[-2,1,1]]]
+ [[1,0,-1],[2,-1,-1]]]
def WeylDim(type, coeffs):
}}}
--
--
Ticket URL: <http://trac.sagemath.org/ticket/2808#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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