2. Finite sets
• A set is to be said finite if there is one-to-one
correspondence between the elements in the
set and the elements in some set n.
where n ∈ N
n is said cardinality of a set.
3. Infinite sets
• A set is an infinite set if it is not finite.
• Two types of infinite sets
– Countably infinite set
– Uncountably infinite set { ex. R, }
• A set is to be said countably infinite if there is
one-to-one correspondence between the
elements in the set and the elements in set N.
• ex . set of odd positive integers is a countable
infinite set.
4. Cartesian Product
• Let A and B be sets. The Cartesian product of A
and B, denoted by A × B, is the set of all
ordered pairs (a, b), where a ∈ A and b ∈ B.
Hence,
• A × B = {(a, b) | a ∈ A ∧ b ∈ B}.
• What is the Cartesian product of A = {1, 2} and
B = {a, b, c}?
Solution: The Cartesian product A × B is
A × B = {(1, a), (1, b), (1, c), (2, a), (2, b), (2, c)}.
6. • Suppose that 109 of 150 students at VS
college take at least one of the following
computer languages: P
7. • Among 150 faculty members in an institute,
55 are connected with each other through
Facebook and 85 are connected through
WhatsApp. 30 faculty members do not have
Facebook or WhatsApp accounts. Calculate
the number of faculty members connected
only through Facebook accounts?
