Infinity symbol Infinity symbol The infinity symbol (sometimes called the lemniscate) is a mathematical symbol representing the concept of infinity. The shape of a sideways figure eight has a long pedigree; for instance, it appears in the cross of Saint Boniface, wrapped around the bars of a Latin cross. However, John Wallis is credited with introducing the infinity symbol with its mathematical meaning in 1655, in his "De sectionibus conicis". Wallis did not explain his choice of this symbol, but it has been conjectured to be a variant form of a Roman numeral for 1,000 (originally CIƆ, also CƆ), which was sometimes
Legendre symbol alternative expressions for the Legendre symbol were devised in order to produce various proofs of the quadratic reciprocity law. The above properties, including the law of quadratic reciprocity, can be used to evaluate any Legendre symbol. For example: Or using a more efficient computation: The article Jacobi symbol has more examples of Legendre symbol manipulation. Legendre symbol In number theory, the Legendre symbol is a multiplicative function with values 1, −1, 0 that is a quadratic character modulo an odd prime number "p": its value on a (nonzero) quadratic residue mod "p" is 1 and on a non-quadratic residue ("non-residue")