Nephrite such as Lantian, Shaanxi, were also in great demand). There, white and greenish nephrite jade is found in small quarries and as pebbles and boulders in the rivers flowing from the Kuen-Lun mountain range northward into the Takla-Makan desert area. River jade collection was concentrated in the Yarkand, and the White Jade (Yurungkash) and Black Jade (Karakash) Rivers in Khotan. From the Kingdom of Khotan, on the southern leg of the Silk Road, yearly tribute payments consisting of the most precious white jade were made to the Chinese imperial court and there transformed into "objets d'art" by skilled artisans, as
Tensor product of quadratic forms from this that if we have diagonalizations of our quadratic forms (which is always possible if formula_9 is invertible) such that then the tensor product has diagonalization Tensor product of quadratic forms The tensor product of quadratic forms is most easily understood when one views the quadratic forms as "quadratic spaces". If "R" is a commutative ring where "2" is invertible, and if formula_1 and formula_2 are two quadratic spaces over "R", then their tensor product formula_3 is the quadratic space whose underlying "R"-module is the tensor product formula_4 of "R"-modules and whose quadratic form is the quadratic form associated