Jacques Offenbach (June 20, 1819 -October 4, 1880), composer and cellist, the creator of "La vie Parisienne" and an originator of the operetta form, a precursor of the modern musical comedy. He wrote a great deal of dance music, particularly for the can-can.
... as "either of those element(s) of the field whose square equals b2 - 4ac". In some fields, some elements have no square roots and some have two; only zero has just one ...