
\
{{0}, {0, 1}, {0, 1, 2}} = {0}.
A B A∩B = ∅ A B
A B
A \B A
B {0, 1, 2} \ {2, 3, 4} = {0, 1}.
R
R A A
R \A A = R \A
R
P
A A =
S
R
B, C ∈ R
B, C ∈ R
B = C B ∩C = ∅
R = {{0, 1}, {2}, {3, 4, 5}} A = {0, 1, 2, 3, 4, 5} R
A
a b
a b {{a, b}, {a}} (a, b)
(a
0
, b
0
) = (a
1
, b
1
)
a
0
= a
1
b
0
= b
1