`red'
-----

red(RAT)
     :: RAT $@$rLsJ,$7$?$b$N(J.

RETURN
     $@M-M}<0(J
RAT
     $@M-M}<0(J

   * Asir $@$OM-M}?t$NLsJ,$r>o$K<+F0E*$K9T$&(J. $@$7$+$7(J, $@M-M}<0$K$D$$$F$ODL(J
     $@J,$O9T$&$,(J, $@LsJ,$O%f!<%6!<$,;XDj$7$J$$8B$j9T$o$J$$(J. $@$3$NLsJ,$r9T(J
     $@$&%3%^%s%I$,(J red $@$G$"$k(J.
   * EZGCD $@$K$h$j(J RAT $@$NJ,;R(J, $@J,Jl$rLsJ,$9$k(J.
   * $@=PNO$5$l$kM-M}<0$NJ,Jl$NB?9`<0$O(J, $@3F78?t$N(J GCD $@$,(J 1 $@$N@0?t78?tB?(J
     $@9`<0$G$"$k(J. $@J,;R$K$D$$$F$O@0?t78?tB?9`<0$H$J$k$H$O8B$i$J$$(J.
   * GCD $@$OBgJQ=E$$1i;;$J$N$G(J, $@B>$NJ}K!$G=|$1$k6&DL0x;R$O2DG=$J8B$j=|(J
     $@$/$N$,K>$^$7$$(J. $@$^$?(J, $@J,Jl(J, $@J,;R$,Bg$-$/$J$C$F$+$i$N$3$NH!?t$N8F(J
     $@$S=P$7$O(J, $@Hs>o$K;~4V$,3]$+$k>l9g$,B?$$(J. $@M-M}<01i;;$r9T$&>l9g$O(J, 
     $@$"$kDxEYIQHK$K(J, $@LsJ,$r9T$&I,MW$,$"$k(J.

     [0] (x^3-1)/(x-1);
     (x^3-1)/(x-1)
     [1] red((x^3-1)/(x-1));
     x^2+x+1
     [2] red((x^3+y^3+z^3-3*x*y*z)/(x+y+z));
     x^2+(-y-z)*x+y^2-z*y+z^2
     [3] red((3*x*y)/(12*x^2+21*y^3*x));
     (y)/(4*x+7*y^3)
     [4] red((3/4*x^2+5/6*x)/(2*y*x+4/3*x));
     (9/8*x+5/4)/(3*y+2)

$@;2>H(J
     `nm', `dn', `gcd', `ptozp'

