Infinity symbol in bookbinding to indicate that a book is printed on acid-free paper and will therefore be long-lasting. In modern mysticism, the infinity symbol has become identified with a variation of the ouroboros, an ancient image of a snake eating its own tail that has also come to symbolize the infinite, and the ouroboros is sometimes drawn in figure-eight form to reflect this identification, rather than in its more traditional circular form. In the works of Vladimir Nabokov, including "The Gift" and "Pale Fire", the figure-eight shape is used symbolically to refer to the Möbius strip and the infinite, for instance
Actual infinity Actual infinity In the philosophy of mathematics, the abstraction of actual infinity involves the acceptance (if the axiom of infinity is included) of infinite entities, such as the set of all natural numbers or an infinite sequence of rational numbers, as given, actual, completed objects. This is contrasted with potential infinity, in which a non-terminating process (such as "add 1 to the previous number") produces a sequence with no last element, and each individual result is finite and is achieved in a finite number of steps. The ancient Greek term for the potential or improper infinite was "apeiron" (unlimited or