Re: poldisc variable must be x or y ?

[Dirk Laurie <dirk.laurie@gmail.com>]

To get an informative error message, do this:

? type(Pol(z/a+1,z))
  ***   at top-level: type(Pol(z/a+1,z))
  ***                      ^-------------
  *** Pol: incorrect priority in gtopoly: variable a < z

Op Do. 21 Feb. 2019 om 09:58 het Dirk Laurie <dirk.laurie@gmail.com> geskryf:
>
> If you do poldisc(z/a+1,z) first in a fresh session, there is no problem.
>
> However, first doing poldisc(x/a+1) defines a variable a which has
> higher precedence than z and therefore is the default variable, and my
> not appear to a negative power in the pol functions. poldisc(a/z+1)
> works.
>
> Op Do. 21 Feb. 2019 om 03:35 het Jacques Gélinas
> <jacquesg00@hotmail.com> geskryf:
> >
> > $ poldisc(x/a+1)
> > 1
> > $ poldisc(y/a+1)
> > 1
> > $ poldisc(z/a+1)
> >   ***   at top-level: poldisc(z/a+1)
> >   ***                 ^--------------
> >   *** poldisc: incorrect type in poldisc (t_RFRAC).
> > $ poldisc(z/a+1,z)
> >   ***   at top-level: poldisc(z/a+1,z)
> >   ***                 ^----------------
> >   *** poldisc: incorrect type in poldisc (t_RFRAC).
> > $ version
> > [2, 12, 0, 23528, "62f3ec361"]
> >
> > Jacques Gélinas
> >