Relation
For example, let
R1 = {<1, 2> , <2, 2>}
{1, 2}
{1, 2} ,
and
R2 = {<a, b> , <b, b>}
{a, b}
{a, b} .
Then R1 = R2 if and only if a = 1 and
b = 2.
Definition (equality of n-ary relation):
An n-ary relation
R1
A1
...
An
and
an m-ary relation
R2
B1
...
Bm
are equal
if and only if m = n, Ai = Bi
for each i,
1
i
n , and
R1 = R2 as a set of ordered n-tuples.