Ilya Zakharevich on Thu, 18 Oct 2001 16:55:19 -0400


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Re: pari-2.2.1.alpha released 

On Thu, Oct 18, 2001 at 05:59:03PM +0200, Karim BELABAS wrote:
>   * subst(P, x^n, y) now works [it's not possible to substitute arbitrary
>   algebraic expressions, only monic monomials].

Is it desirable to do The Right Thing?  make

  subst(P, Q, y)

a shortcut for

  { subst_poly(pol, from, to) = 
    local(t);
    subst(lift(Mod(pol,from-'t)),'t,to)
  }

if the existing algorithms cannot do it (only taking into account the
ordering of variables, so lift will always work w.r.t. 't).

[ BTW, why do I need to put ticks on t?  Why I cannot lift(...,'t)? ]

Ilya