#13800: sign error in Steenrod algebra multiplication
--------------------------------------+-------------------------------------
Reporter: cnassau | Owner: jhpalmieri
Type: defect | Status: positive_review
Priority: minor | Milestone: sage-5.5
Component: algebraic topology | Resolution:
Keywords: Steenrod algebra | Work issues:
Report Upstream: N/A | Reviewers: John Palmieri
Authors: Christian Nassau | Merged in:
Dependencies: | Stopgaps:
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Changes (by jhpalmieri):
* status: needs_review => positive_review
Old description:
> There is a sign error in the Steenrod multiplication routine at odd
> primes: with
>
> {{{
> A=SteenrodAlgebra(3)
> Q=A.Q_exp
> P=A.P
> print (Q(0,1)*P(3))*Q(1,1)
> print Q(0,1)*(P(3)*Q(1,1))
> }}}
>
> one gets
>
> {{{
> Q_0 Q_1 Q_2
> 2 Q_0 Q_1 Q_2
> }}}
>
> Only the 2nd answer is correct.
New description:
There is a sign error in the Steenrod multiplication routine at odd
primes: with
{{{
A=SteenrodAlgebra(3)
Q=A.Q_exp
P=A.P
print (Q(0,1)*P(3))*Q(1,1)
print Q(0,1)*(P(3)*Q(1,1))
}}}
one gets
{{{
Q_0 Q_1 Q_2
2 Q_0 Q_1 Q_2
}}}
Only the 2nd answer is correct.
---------
Apply [attachment:trac_13800-cn.patch].
--
Comment:
I couldn't get your patch to apply, so I made a new one. Mercurial queues
are a good way to deal with this sort of situation, in my experience.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13800#comment:4>
Sage <http://www.sagemath.org>
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