Figure skating they may be distinguished. The two categories of jumps are toe jumps and edge jumps. The number of rotations performed in the air determines whether the jump is a single, double, triple, or quadruple (commonly known as a "quad"). The simplest jump begins with a waltz jump which can only be done in a half-leap and is not classified as a single, double, or triple jump. Senior-level male single skaters perform mostly triple and quadruple jumps in competition. Triple jumps other than the Axel are commonly performed by female single skaters. It is extremely rare for a female skater to
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