B = { x | x
A
x
B }Unit 13 Answers
1.
a) A
B = { x | x
A
x
B }
= { x | x
B
x
A } = B
A
b) A
B = { x | x
A
x
B }
= { x | x
B
x
A } =
B
A
2. For an arbitrary element x in the universe,
x
x
A
B
( x
A
x
B )
( x
A
x
B )
( x
A
x
B )
( x
x
)
x
3. For an arbitrary element x in the universe,
x
A
( B
C )
( x
A
x
B
C )
( x
A
( x
B
x
C ))
(( x
A
x
B )
x
C )
x
( A
B )
C