The tensor product can be used as a means of taking of two subschemes in a scheme: consider the
-algebras
,
, then their tensor product is
, which describes the intersection of the algebraic curves f = 0 and g = 0 in the affine plane over C.
intersections
More generally, if
is a commutative ring and
are ideals, then
, with a unique isomorphism sending
to
.
Tensor products can be used as a means of changing coefficients. For example,
and
.
Tensor products also can be used for taking of affine schemes over a field. For example,
is isomorphic to the algebra
which corresponds to an affine surface in
if f and g are not zero.
products
Given
-algebras
and
whose underlying rings are , the tensor product
becomes a graded commutative ring by defining
for homogeneous
,
,
, and
.
graded-commutative rings
Extension of scalars
Tensor product of modules
Tensor product of fields
Linearly disjoint
Multilinear subspace learning
Kassel, Christian (1995), , Graduate texts in mathematics, vol. 155, Springer, ISBN 978-0-387-94370-1.
Quantum groups
Lang, Serge (2002) [first published in 1993]. Algebra. Graduate Texts in Mathematics. Vol. 21. Springer. 0-387-95385-X.