Date: Tue, 13 Jul 1999 07:54:35 -0600 (CST)

Subject: infinity
Name: Mark

Who is asking: Parent

Level: All

Question:

There is a symbol that looks like a sideways 8 that is used to represent infinity. Does it have a name?

Hi Mark,

Earliest Uses of Various Mathematical Symbols, a Web site maintained by a High School teacher Jeff Miller, is a wonderful source for answering this type of question. (Infinity is in the calculus section.) Jeff refers to "Cajori, Florian. A History of Mathematical Notations. 2 volumes. Lasalle, Illinois: The Open Court Publishing
Co., 1928-1929" the definitive source on mathematical notation.

Cajori says that the infinity symbol was introduced by John Wallis (1616-1703) in 1655 in his De sectionibus conicis (On Conic Sections).
Wallis also used the infinity symbol in various passages of his Arithmetica infinitorum (Arithmetic of Infinites) (1655). In "Zero to Lazy Eight", Alexander Humez, Nicholas Humez, and Joseph Maguire write: "Wallis was a classical scholar and it is possible that he derived the symbol for infinity from the old Roman sign for 1,000, CD, also written M--though it is also possible
that he got the idea from the lowercase omega, omega being the last letter of the Greek alphabet and thus a metaphor of long standing for the upper limit, the end."

Cheers,

Doug and Penny