> From: "Viktor T. Toth" <vttoth at vttoth.com>
> Date: Mon, 30 Sep 2013 10:44:34 -0400
>
> > Q: why is ug not computed automatically, since lg is?
>
> To be honest, I don't remember, but let me take an educated guess: depending
> on the algebraic complexity of lg, the automatic calculation of ug may be
> prohibitively costly, and in many cases, ug is not needed when a frame base
> is used. Given this and the fact that if needed, ug can be computed
> trivially may be the reason. (May have been _my_ reason. It was too long
> ago, I just don't remember how much of this is code I wrote vs. code I
> "rescued" from earlier, incomplete implementations.)
Ok, this makes sense. You may want to simplify lg, like in some
examples, before computing its inverse.
>
> > would it be appropriate/correct to add a reference to see `petrov'?
>
> You mean as a usage example? Yes, I think it would be appropriate.
I pushed this reference.
Leo