On Thu, Dec 9, 2010 at 10:03 PM, Rob Beezer <goo...@beezer.cotse.net> wrote: > Is there any objection to deprecating the current .adjoint() function > (which returns a matrix of cofactors) and renaming it as the > "adjugate"? With all the usual procedures and warnings for the > deprecation. That would begin the process to free up "adjoint" for > something else (ideally the conjugate-transpose).
I've been unable to reply on this before, and today after receiving a comment on ticket #10501 I commented right there, which was possibly a bit unpolite given the lapse of time and that I didn't post that commentto this thread (if so I apologize). Anyway, here's a copy of my post, in case it's helpful: I already stated some objections, but I'll repeat: On deprecating "adjoint" meaning "matrix of cofactors" 1. it's standard terminology and has meant this in sage for long 2. "adjugate" is newer and (IMO) less standard terminology -- in particular it has no obvious translations On using "adjoint" meaning "conjugate transpose" 3. "conjugate transpose" is easy to say, and it's really what is meant 4. the "adjoint operator" for a matrix seems ill-defined, because a matrix is not an operator but only a representation of an operator in some basis. Moreover, if there are two colliding usages of the name "adjoint", I would find it more reasonable to keep the usage that is already traditional in Sage. The usage of "adjoint" is ubiquitous in relation to quadratic forms afaict (and, as John Cremona pointed out, is where the term originates with Gauss on ternary quadratic forms). I also pointed out a reference to Bourbaki which I already posted above. I still haven't found a reference for "adjugate" which satisfies me (I mean, where does it originate?) or a good reference for how to use "adjoint of a matrix" as meaning "conjugate transpose" in reference to adjoint operators without eventually causing some pain when using it in the real world where not all bases are orthogonal (not even all vector spaces have inner product). OTOH, I do certainly appreciate that transpose and conjugate transpose is used quite a lot, and thus I think it really deserves all the shortcuts proposed (T, H, star, etc). Gonzalo -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
