21
Example 1
•
s
= {E} (graphs)
•
What does this formula say ?
8
u.
8
v.[
lfp
R, x, y
f
(R, x, y)](u,v)
where
f
(R, x, y) =
(E(x,y)
Ç
9
z.(E(x,z)
Æ
R(z,y))
