Changes between Version 10 and Version 12 of Ticket #12529


Ignore:
Timestamp:
10/09/20 08:12:55 (8 weeks ago)
Author:
slelievre
Comment:

Thanks!

Legend:

Unmodified
Added
Removed
Modified
  • Ticket #12529

    • Property Status changed from needs_review to positive_review
    • Property Reviewers changed from to Kiran Kedlaya
  • Ticket #12529 – Description

    v10 v12  
    1 On [http://groups.google.com/group/sage-support/browse_thread/thread/b90fbb622ddb55ab sage-support], Oleksandr Kazymyrov reported the following:
     1Condensed version of a report by Oleksandr Kazymyrov [http://groups.google.com/group/sage-support/browse_thread/thread/b90fbb622ddb55ab on sage-support].
     2
     3Define `g` by modding out in a multivariate polynomial ring:
    24{{{
    35sage: gens = 'y a0 a1 a2 b0 b1 b2 c1 c2 d0 d1 d2 d3 d4 d5 d6 d7'.split()
     
    911sage: G = A.subs({y: F}) + C
    1012sage: g = G.mod(y^8 + y)
     13}}}
     14
     15After modding out by a polynomial of degree 8 in `y`,
     16the degree of `g` in `y` should be at most 7.
     17
     18Up to Sage 9.1.rc1:
     19{{{
    1120sage: g.degree(y)
    122114
    1322}}}
    1423
    15 This is now fixed and we add a doctest:
     24After #27508 (Force tail reduction in polynomial quotient ring),
     25merged in Sage 9.1.rc2:
    1626{{{
    1727sage: g.degree(y)
     
    1929}}}
    2030
    21 The problem may have been in libsingular,
    22 rather than in Singular.
     31The problem was libsingular not doing tail reduction
     32when calling Singular.
    2333
    24 It may have been tail reduction not being done.
     34This ticket adds the above example as a doctest.