Pounamu Pounamu Pounamu refers to several types of hard, durable and highly valued nephrite jade, bowenite, or serpentinite stone found in southern New Zealand. Pounamu is the Māori name. These rocks are also generically known as "greenstone" in New Zealand English. There are two systems for classifying pounamu. Geologically, the rock falls into the three categories named above, but Māori classify pounamu by appearance. The main classifications are "kawakawa", "kahurangi", "īnanga", and "tangiwai". The first three are nephrite jade, while "tangiwai" is a form of bowenite. In modern usage "pounamu" almost always refers to nephrite jade. Pounamu is generally found in
Tensor product of quadratic forms 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 to the tensor product of the bilinear forms associated to formula_5 and formula_6. In particular, the form formula_7 satisfies (which does uniquely characterize it however). It follow