Megszámlálhatóan

Megszámlálhatóan is a Hungarian word that translates to "countably" in English. It is most commonly used in mathematics, particularly in set theory, to describe the size of a set. A set is considered countably infinite if its elements can be put into a one-to-one correspondence with the set of natural numbers (1, 2, 3, ...). This means that even though the set has infinitely many elements, we can still list them in an order and assign a unique natural number to each element.

The set of natural numbers itself is the prime example of a countably infinite set. Other examples include the set of integers (..., -2, -1, 0, 1, 2, ...) and the set of rational numbers (fractions). Despite appearances, these sets can be systematically enumerated, demonstrating their countable nature. Sets that are not countable are called uncountable. A famous example of an uncountable set is the set of real numbers. The concept of countability is fundamental to understanding different sizes of infinity.