The tensor product
of two modules over a commutative
ring
is a module equipped with a bilinear
function
that has the universal property among bilinear
functions out of
.
In other words, for every
-module
, each
-bilinear function
factors uniquely
through a module homomorphism
.
The construction specializes to the vector space tensor product when is a field. Tensor products also
occur for group representations, sheaves
of modules, vector bundles,
and other algebraic objects.
For linear transformations between finite-dimensional vector spaces, the tensor product is represented by the Kronecker product of their matrices after vector bases are chosen.