тензорное произведение
математика тензорное произведение
A function of two vector spaces, U and V, which returns the space of linear maps from V's dual to U. Tensor product has natural symmetry in interchange of U and V and it produces an associative "multiplication" on vector spaces. When all the vector spaces are the same, permutation of the factors doesn't change the space and so constitutes an automorphism. These permutation-induced iso-auto-morphisms form a group which is a model of the group of permutations.