Opened 7 years ago

Closed 7 years ago

#13800 closed defect (fixed)

sign error in Steenrod algebra multiplication

Reported by: cnassau Owned by: jhpalmieri
Priority: minor Milestone: sage-5.6
Component: algebraic topology Keywords: Steenrod algebra
Cc: Merged in: sage-5.6.beta2
Authors: Christian Nassau Reviewers: John Palmieri
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by jhpalmieri)

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 trac_13800-cn.patch.

Attachments (1)

trac_13800-cn.patch (1.4 KB) - added by jhpalmieri 7 years ago.

Download all attachments as: .zip

Change History (7)

comment:1 Changed 7 years ago by cnassau

  • Status changed from new to needs_review

comment:2 Changed 7 years ago by jhpalmieri

  • Authors set to Christian Nassau
  • Reviewers set to John Palmieri

Hi Christian, welcome aboard. The patch looks very good, except for a very minor detail: the example in the doctest should be indented one more space. Fix that, and I'll give it a positive review. By the way, if you want, you can add your name to the list of account names on the wiki.

comment:3 Changed 7 years ago by cnassau

Hi John, the indentation is now fixed. Hope I'll have something less trivial to contribute some day ;-)

Changed 7 years ago by jhpalmieri

comment:4 Changed 7 years ago by jhpalmieri

  • Description modified (diff)
  • Status changed from needs_review to positive_review

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.

comment:5 Changed 7 years ago by jdemeyer

  • Milestone changed from sage-5.5 to sage-5.6

comment:6 Changed 7 years ago by jdemeyer

  • Merged in set to sage-5.6.beta2
  • Resolution set to fixed
  • Status changed from positive_review to closed
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