44
Example
Let f = {(1,a),(2,b),(3,c),(4,d)}
Let f = {(1,a),(2,b),(3,c),(4,d)}
1
2
3
4
a
b
c
d
| R°f - S | =
|{(a,b)(b,c)(c,d)(d,b)} - {(a,b)(b,c)(c,b)(d,b)} |
= |{(c,d)}| = 1
|S ° f - R | = |{(1,2)(2,3)(3,2)(4,2)} -
{(1,2)(2,3)(3,4)(4,2)}|
=
|{(3,2)}| = 1
-1
R
S
E(f) = 1+1 =
2