`nm', `dn'
----------

nm(RAT)
     :: RAT $@$NJ,;R(J.
dn(RAT)
     :: RAT $@$NJ,Jl(J.

RETURN
     $@@0?t$^$?$OB?9`<0(J
RAT
     $@M-M}?t$^$?$OM-M}<0(J

   * $@M?$($i$l$?M-M}?t$^$?M-M}<0$NJ,;R5Z$SJ,Jl$rJV$9(J.
   * $@M-M}?t$N>l9g(J, $@J,Jl$O>o$K@5$G(J, $@Id9f$OJ,;R$,;}$D(J.
   * $@M-M}<0$N>l9g(J, $@C1$KJ,Jl(J, $@J,;R$r<h$j=P$9$@$1$G$"$k(J. $@M-M}<0$KBP$7$F(J
     $@$O(J, $@LsJ,$O<+F0E*$K$O9T$o$l$J$$(J. `red()'$@$rL@<(E*$K8F$S=P$9I,MW$,$"(J
     $@$k(J.

     [2] [nm(-43/8),dn(-43/8)];
     [-43,8]
     [3] dn((x*z)/(x*y));
     y*x
     [3] dn(red((x*z)/(x*y)));
     y

$@;2>H(J
     `red'

