> > > This is in some sense good, since we don't have to care about the > derivative at zero, > but in an other sense it is not so good, since the subdifferential ∂abs(0) > = [0,1] is a bounded and with this definition one could come to the false > conclusion that abs(x) > has a pole, althoug by taking limits one can easily see that it should be > bounded at zero. > > > > Sorry I meant ∂abs(0) = [-1,1] ...
And another thing to add: I think the only clean solution could be a warning like: "Warning: This is not a derivative in the classical sense!" But I don't know if this is really worth the effort ... -- 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 http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
