`dp_ptozp', `dp_prim'
---------------------

dp_ptozp(DPOLY)
     :: $BDj?tG\$7$F78?t$r@0?t78?t$+$D78?t$N@0?t(B GCD $B$r(B 1 $B$K$9$k(B.

dp_prim(DPOLY)
     :: $BM-M}<0G\$7$F78?t$r@0?t78?tB?9`<078?t$+$D78?t$NB?9`<0(B GCD $B$r(B 1
     $B$K$9$k(B.

RETURN
     $BJ,;6I=8=B?9`<0(B

DPOLY
     $BJ,;6I=8=B?9`<0(B

   * `dp_ptozp()' $B$O(B,  `ptozp()' $B$KAjEv$9$kA`:n$rJ,;6I=8=B?9`<0$K(B
     $BBP$7$F9T$&(B. $B78?t$,B?9`<0$r4^$`>l9g(B, $B78?t$K4^$^$l$kB?9`<06&DL0x;R$O(B
     $B<h$j=|$+$J$$(B.

   * `dp_prim()' $B$O(B, $B78?t$,B?9`<0$r4^$`>l9g(B,
     $B78?t$K4^$^$l$kB?9`<06&DL0x;R(B $B$r<h$j=|$/(B.

     [208] X=dp_ptod(3*(x-y)*(y-z)*(z-x),[x]);
     (-3*y+3*z)*<<2>>+(3*y^2-3*z^2)*<<1>>+(-3*z*y^2+3*z^2*y)*<<0>>
     [209] dp_ptozp(X);
     (-y+z)*<<2>>+(y^2-z^2)*<<1>>+(-z*y^2+z^2*y)*<<0>>
     [210] dp_prim(X);
     (1)*<<2>>+(-y-z)*<<1>>+(z*y)*<<0>>

$B;2>H(B
     *Note `ptozp': ptozp.

