I previously had not looked at the further discussion in that report, but the discussion of branches of the log function and the Sage "simplification" shows it is not a parsing problem. Since log() is in general multivalued, any answer that ignores this possibility may fall into a trap. Setting a domain to something or other does not necessarily avoid the trap. An example that is simpler and perhaps reminiscent of this kind of error is to assert that sqrt(x^2) is x or abs(x), when there are (except if x=0) TWO square roots, x, -x. Even if you know that x is positive, there are still two square roots. sqrt(9) has 2 values. Unless you want to define sqrt as something else. Do you? How about log() in the current example.. RJF
On Thursday, November 28, 2019 at 2:15:55 PM UTC-8, rjf wrote: > > I just tried the problem in Maxima 5.40.0 ; the result is correct as I > assume > Emmanuel also discovered. The "fix" suggested by the poster of Trac#28431 > (to divert some class of integral problems to sympy) does not strike me > as plausible. > Maybe something about Sage parsing of a minus sign?? > RJF > > > On Wednesday, November 20, 2019 at 10:46:22 AM UTC-8, Emmanuel Charpentier > wrote: >> >> I may be wrong, but a bit of exploration of Trac#28431 >> <https://trac.sagemath.org/ticket/28431>, which seemed fairly innocuous, >> may demonstrate a basic failure in *our interface* to Maxima, which is, >> IMHO, more severe than a bug in Maxima... >> I also checkef that's not a side effect of the domain:complex setup... >> A look by someone who knows what he's doing in this region of Sage may be >> worthy... >> > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/8f226c89-d638-4192-909a-7e7ea1e64b9c%40googlegroups.com.
