Copyright (C) 1997 $BBgFb(B $BBs<B(B, $B6a;3(B $BN4(B

	*** MGTP $B>e$N5"G<O@M}%W%m%0%i%_%s%0%7%9%F%`$NNcBj(B ***

$B!TCm!U(B
$B$3$N%W%m%0%i%`$O(B, $B2>@b8uJd$H$7$F9M$($i$l$kO@M}<0$r$9$Y$F2r$H$7$F@8@.$9(B
$B$k$N$G(B, $B@5$7$$2r$r40A4$KNs5s$9$k$N$O:$Fq$G$9!#$7$?$,$C$F(B, $B0J2<$NNcBj$N(B
$B2r$O0lHLE*$J7A<0$r@bL@$r$7$F$$$^$9!#(B


$B!ZNcBj(B1$B![(B

  $B@5;vNc(B	r(a,a), r(a,b), r(a,c), r(a,d), r(b,b), 
		r(b,c), r(b,d), r(c,c), r(c,d), r(d,d)
  $BIi;vNc(B	r(b,a), r(c,a), r(c,b), r(d,a), r(d,b), r(d,c)

  $BGX7JCN<1(B	p(X,X).  
		q(a,b).  q(b,c).  q(c,d). 
		p(X,Y), q(Y,Z) --> p(X,Z).  
  $B$KBP$9$k2r$H$7$F(B, 
		r(a,X).  
		r(X,d).  
		r(X,X).  
		....
		p(X,Y) --> r(X,Y).  
		....
		q(X,Y) --> r(X,Y).  
		....
		p(X,Y), q(Y,Z) --> r(X,Z).  
		....
  $B$rF@$k(B. 

$B!ZNcBj(B2$B![(B
  $B@5;vNc(B	plus(0,0,0), plus(0,1,1), ...

  $BIi;vNc(B	plus(0,0,1), plus(0,1,0), ...

  $BGX7JCN<1(B	s(0,1).  s(1,2).  ....

  $B$KBP$9$k2r$H$7$F(B, 
		plus(0,X,X).  
		plus(X,0,X).  
		....
		plus(X,Y,Z), s(X,X1), s(Z,Z1) --> plus(X1,Y,Z1).  
		....
  $B$rF@$k(B. 


$B$?$@$7(B, $BF@$i$l$k2r$O(B, ($B>e5-$N2r$r4^$`(B)$BBEEv$J<0$9$Y$F$H$J$k(B. 
($B$?$H$($PNcBj(B1 $B$N>l9g(B, 
		p(b,X), q(X,Y) --> r(b,Y).  
		p(X,c), p(Y,X) --> r(Y,d).  
 $B$J$I$b2r$H$7$F8=$l$k(B. )

$B2r$H$J$k<0$ND9$5$K$D$$$F$O(B, MGTP$B%=!<%9$N(B Intra-construction 
$B$r9T$J$&ItJ,$G@)8B$r2C$($F$$$k(B. 
( fff2_less(Len,3) $B$H$$$&=R8l$K$h$C$F(B, $BD9$5$r(B 3 $B0J2<$K(B
 $B$7$F$$$k(B)

$B0J>e(B
