Hi all! There appears to be a bug involving block orders. The equality for TermOrder does not take lengths into account, so two different block orderings are considered equal. As a result, trying to change the block sizes of a polynomial ring has no effect, as the ring is cached.
sage: R = PolynomialRing(QQ, 6, 'x', order="lex(1),lex(5)") sage: S = R.change_ring(order="lex(2),lex(4)") sage: R.term_order() != S.term_order() False sage: R is S True sage: TermOrder("lex(1),lex(5)") == TermOrder("lex(2),lex(4)") True Although the source code for TermOrder mentions that lengths are not considered for equality, this seems to be incorrect behaviour in case of block orderings. I am using Sage 8.1 on OS X 10.13. Markus -- 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.