Köchel catalogue 225: The New Complete Edition" contains premiere performances of previously lost compositions and never recorded fragments, as well as key works in alternative versions and recordings of legendary historic performances. Köchel catalogue The Köchel catalogue () is a chronological catalogue of compositions by Wolfgang Amadeus Mozart, originally created by Ludwig von Köchel, in which the entries are abbreviated "K." and "KV". The numbers of the Köchel catalogue reflect the continuing establishment of a complete chronology of Mozart's works, and provide a shorthand reference to the compositions. According to Köchel's counting, "Requiem in D minor" is the 626th piece Mozart composed,
19th century in science a cube twice the volume of a given cube, nor to construct a square equal in area to a given circle. Mathematicians had vainly attempted to solve all of these problems since the time of the ancient Greeks. On the other hand, the limitation of three dimensions in geometry was surpassed in the 19th century through considerations of parameter space and hypercomplex numbers. In the later 19th century, Georg Cantor established the first foundations of set theory, which enabled the rigorous treatment of the notion of infinity and has become the common language of nearly all mathematics. Cantor's set theory,