Infinity symbol symbol is encoded in Unicode at and in LaTeX as codice_1: formula_4. The Unicode set of symbols also includes several variant forms of the infinity symbol, that are less frequently available in fonts: , and in block Miscellaneous Mathematical Symbols-B. The acid-free paper symbol mentioned above is encoded separately as . 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
Hilbert symbol reciprocity law follows from the Artin reciprocity law and the definition of the Hilbert symbol in terms of the Artin symbol. If "K" is a number field containing the "n"th roots of unity, "p" is a prime ideal not dividing "n", π is a prime element of the local field of "p", and "a" is coprime to "p", then the power residue symbol () is related to the Hilbert symbol by The power residue symbol is extended to fractional ideals by multiplicativity, and defined for elements of the number field by putting ()=() where ("b") is the principal ideal generated