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 actu non datur" as an irrefutable principle. (G. Cantor [3, p. 174]) The number of points in a segment one ell long is its true measure. (R. Grosseteste [9, p. 96]) Actual infinity exists in number, time and quantity. (J. Baconthorpe [9, p. 96]) During the Renaissance and by early modern times the voices in favor of actual infinity were rather rare. The continuum actually consists of infinitely many indivisibles (G. Galilei [9, p. 97]) I am so in favour of actual infinity. (G.W. Leibniz [9, p. 97]) The majority agreed with the well-known quote of Gauss: I protest against