9.5.12 `set_field'
------------------

set_field(ROOTLIST)
     :: $BBe?tBN$r4pACBN$H$7$F@_Dj$9$k(B.

RETURN
     0

ROOTLIST
     `root' $B$N%j%9%H(B

   * `root' $B$N%j%9%H(B ROOTLIST $B$G@8@.$5$l$kBe?tBN$r4pACBN$H$7$F@_Dj$9$k(B.

   * `root' $B$OFbItE*$K=g=x$E$1$i$l$F$$$k$N$G(B, ROOTLIST $B$O=89g$H$7$F;XDj(B
     $B$9$l$P$h$$(B. ($B=g=x$O5$$K$7$J$/$F$h$$(B.)

     [0] A=newalg(x^2+1);
     (#0)
     [1] B=newalg(x^3+A);
     (#1)
     [2] C=newalg(x^4+B);
     (#1)
     [3] set_field([C,B,A]);
     0

$B;2>H(B
     *Note `algtodalg dalgtoalg dptodalg dalgtodp': algtodalg dalgtoalg
     dptodalg dalgtodp.

