<P> The infinity symbol may also be used to represent a point at infinity, especially when there is only one such point under consideration . This usage includes, for instance, the infinite point of a projective line, and the point added to a topological space T (\ displaystyle T) to form its one - point compactification T ∞ (\ displaystyle T_ (\ infty)). </P> <P> In areas other than mathematics, the infinity symbol may take on other related meanings; for instance, it has been used in bookbinding to indicate that a book is printed on acid - free paper and will therefore be long - lasting . </P> <P> 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 . </P> <P> 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 in these books' descriptions of the shapes of bicycle tire tracks and of the outlines of half - remembered people . The poem after which Pale Fire is entitled explicitly refers to "the miracle of the lemniscate". </P>

What does a cross with an infinity sign mean