`prim', `cont'
--------------

prim(POLY)
     :: POLY $@$N86;OE*ItJ,(J (primitive part).
cont(POLY)
     :: POLY $@$NMFNL(J (content).

RETURN POLY
     $@M-M}?t78?tB?9`<0(J

   * POLY $@$N<gJQ?t$K4X$9$k86;OE*ItJ,(J, $@MFNL$r5a$a$k(J.
   * $@<gJQ?t$N;XDj$,$G$-$J$$$N$G(J, $@<gJQ?t$G$J$$JQ?t$K$D$$$F7W;;$7$?$$>l(J
     $@9g$K$O(J, `ord()' $@$GJQ?t=g=x$rD4$Y$F(J, $@$=$NJQ?t$,<gJQ?t$K$J$k$h$&$K(J
     $@JQ?t$rF~$lBX$($F7W;;$7$F(J, $@$b$H$KLa$9$3$H$K$J$k(J.
   * $@<gJQ?t;XDj$,$G$-$k$h$&2~NI$NM=Dj(J.

     [0] E=(y-z)*(x+y)*(x-z)*(2*x-y);
     (2*y-2*z)*x^3+(y^2-3*z*y+2*z^2)*x^2+(-y^3+z^2*y)*x+z*y^3-z^2*y^2
     [1] prim(E);
     2*x^3+(y-2*z)*x^2+(-y^2-z*y)*x+z*y^2
     [2] cont(E);
     y-z
     [3] subst(prim(subst(E,x,w,z,x),x,z,w,x);
     (y-z)*x-z*y+z^2

$@;2>H(J
     `var', `ord'

