Infinity on High finished the year at number twenty-one on IFPI's list of the "Top 50 Global Best Selling Albums of 2007". "Infinity on High" has shipped over two million copies worldwide. The album also charted inside the top five worldwide, making it the band's most successful and breakthrough album internationally. "Infinity on High" charted all over Europe, debuting at number eight on "Billboard"'s European Albums chart. In Australia, it debuted at its peak of number four on the Australian ARIA Albums Chart. It remained on the Australian chart for a total of fifty weeks, spending its first seven weeks in the top
Legendre symbol 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") is −1. Its value on zero is 0. The Legendre symbol was introduced by Adrien-Marie Legendre in 1798 in the course of his attempts at proving the law of quadratic reciprocity. Generalizations of the symbol include the Jacobi symbol and Dirichlet characters of higher order. The notational convenience of the Legendre symbol inspired introduction of