👉 In mathematics, an infinite set is said to be "definable" if it can be defined in terms of other sets and operations. In other words, a set is definable if there exists a function that maps each element of the set to a unique element of another set (the codomain). This concept allows us to define functions on infinite sets using only finite arguments and results. For example, consider the set of natural numbers $\mathbb{N}$. We can define a function
