Violin Concerto No. 7 (Mozart) to the insertion of new works bearing the numbers K. 271b to K. 271H in the catalogue. He believed that the work was based on a rough sketch of a violin concerto by Mozart from 1777, but states that the original form of the work cannot easily be reconstructed. The uncharacteristic number of passages for the solo violin in the high register, in "pizzicato" (in the second movement), and in double stops in tenths were considered by Einstein to be 19th-century additions. Friedrich Blume, on the other hand, was firmly in favour of the work's authenticity, stating that "not one
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,