Symphony, K. 19b (Mozart) symphonies K. 16 and K. 19 (strings, 2 oboes, and 2 horns). In his third edition of the Köchel catalogue, he dated it to early 1765 in London, and opined that the incipit showed the influence of J. C. Bach's symphonies. His remarks were copied unchanged by the sixth edition of the Köchel catalogue. Neal Zaslaw agreed that the opening was characteristic of J. C. Bach in his book "Mozart's Symphonies", but questioned if this was a legitimate method of dating works, given that the seven symphonies of J. C. Bach beginning in this march-like way were written later than
19th century in science later in the 19th century by the German mathematician Bernhard Riemann; here no parallel can be found and the angles in a triangle add up to more than 180°. Riemann also developed Riemannian geometry, which unifies and vastly generalizes the three types of geometry. The 19th century saw the beginning of a great deal of abstract algebra. Hermann Grassmann in Germany gave a first version of vector spaces, William Rowan Hamilton in Ireland developed noncommutative algebra. The British mathematician George Boole devised an algebra that soon evolved into what is now called Boolean algebra, in which the only numbers were