Triple metre Triple metre Triple metre (or Am. triple meter, also known as triple time) is a musical metre characterized by a "primary" division of 3 beats to the bar, usually indicated by 3 (simple) or 9 (compound) in the upper figure of the time signature, with , , and being the most common examples. The upper figure being divisible by three does not of itself indicate triple metre; for example, a time signature of usually indicates compound duple metre, and similarly usually indicates compound quadruple metre. Shown below are a simple and a compound triple drum pattern. It is reasonably common
Quadruple product Quadruple product In mathematics, the quadruple product is a product of four vectors in three-dimensional Euclidean space. The name "quadruple product" is used for two different products, the scalar-valued scalar quadruple product and the vector-valued vector quadruple product or vector product of four vectors . The scalar quadruple product is defined as the dot product of two cross products: where a, b, c, d are vectors in three-dimensional Euclidean space. It can be evaluated using the identity: or using the determinant: The vector quadruple product is defined as the cross product of two cross products: where a, b, c, d