At Most Countably Infinite Set?

A set is countably infinite if its elements can be put in one-to-one correspondence with the set of natural numbers. In other words, one can count off all elements in the set in such a way that, even though the counting will take forever, you will get to any particular element in a finite amount of time.

What is an at most countable?

A set X is said to be countably infinite (or just countable) iff it has equal cardinality with the natural numbers N. A set X is said to be at most countable iff it is either countable or finite. We say that a set is uncountable if it is infinite but not countable.

Which of the following is a countably infinite set?

Similarly, the set of natural numbers is a set of numbers starting from 1 up to infinite with difference 1 between two consecutive terms. So, natural numbers are a set of countably infinite elements.

Marcus Vance

Marcus Vance

Cybersecurity & Digital Privacy Researcher

Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.