Countable set

In mathematics the term countable is used to describe the size of a set, i.e. the number of elements it contains. The notion of an infinite set is not elementary; it requires a strong sense of abstraction and precision.

Related Topics:
Mathematics - Set - Infinite - Abstraction - Precision

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A set is called countable if the number of elements is finite or if it has the same number of elements as the natural numbers. The term countable stems from the fact that the natural numbers are often called counting numbers. A set with more elements is called uncountable; not all uncountable sets have the same size. The different sizes of infinite sets are investigated in the theory of cardinal numbers.

Related Topics:
Natural number - Uncountable - Cardinal number

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