Changes between Version 10 and Version 12 of Ticket #12529
 Timestamp:
 10/09/20 08:12:55 (6 months ago)
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Ticket #12529

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topositive_review

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Kiran Kedlaya

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Ticket #12529 – Description
v10 v12 1 On [http://groups.google.com/group/sagesupport/browse_thread/thread/b90fbb622ddb55ab sagesupport], Oleksandr Kazymyrov reported the following: 1 Condensed version of a report by Oleksandr Kazymyrov [http://groups.google.com/group/sagesupport/browse_thread/thread/b90fbb622ddb55ab on sagesupport]. 2 3 Define `g` by modding out in a multivariate polynomial ring: 2 4 {{{ 3 5 sage: gens = 'y a0 a1 a2 b0 b1 b2 c1 c2 d0 d1 d2 d3 d4 d5 d6 d7'.split() … … 9 11 sage: G = A.subs({y: F}) + C 10 12 sage: g = G.mod(y^8 + y) 13 }}} 14 15 After modding out by a polynomial of degree 8 in `y`, 16 the degree of `g` in `y` should be at most 7. 17 18 Up to Sage 9.1.rc1: 19 {{{ 11 20 sage: g.degree(y) 12 21 14 13 22 }}} 14 23 15 This is now fixed and we add a doctest: 24 After #27508 (Force tail reduction in polynomial quotient ring), 25 merged in Sage 9.1.rc2: 16 26 {{{ 17 27 sage: g.degree(y) … … 19 29 }}} 20 30 21 The problem may have been in libsingular,22 rather than inSingular.31 The problem was libsingular not doing tail reduction 32 when calling Singular. 23 33 24 It may have been tail reduction not being done.34 This ticket adds the above example as a doctest.