Hi Kwankyu, On 2018-03-15, Kwankyu Lee <ekwan...@gmail.com> wrote: >> sage: R = PolynomialRing(QQ, 6, 'x', order="lex(1),lex(5)") >> sage: S = R.change_ring(order="lex(2),lex(4)") >> sage: S.term_order() >> >> Block term order with blocks: >> (Lexicographic term order of length 1, >> Lexicographic term order of length 5) >> >> Clearly, the term order of S does not seem to be correctly set. >> > > The two term orders are mathematically the same. We cannot say that this > behavior is wrong. What harm does this behavior make?
1. They are programmatically not the same, i.e., in some applications, one of the orders would be more efficient, in other applications, the other order would be more efficient. 2. In the following example, the orders of R and S are supposed to be mathematically different, yet the rings are identical in Sage: sage: R = PolynomialRing(QQ, 6, 'x', order="lex(1),degrevlex(5)") sage: S = R.change_ring(order="lex(2),degrevlex(4)") sage: R is S True So, indeed it is a bug. Cheers, Simon -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
