Tensor Product Functorial Construction

AUTHORS:

• Nicolas M. Thiery (2008-2010): initial revision and refactorization

class sage.categories.tensor.TensorProductFunctor

Bases: sage.categories.covariant_functorial_construction.CovariantFunctorialConstruction

A singleton class for the tensor functor

This functor takes a collection of vector spaces (or modules with basis), and constructs the tensor product of those vector spaces. If this vector space is in a subcategory, say that of Algebras(QQ), it is automatically endowed with its natural algebra structure, thanks to the category Algebras(QQ).TensorProducts() of tensor products of algebras.

The tensor functor is covariant: if A is a subcategory of B, then A.TensorProducts() is a subcategory of B.TensorProducts() (see also CovariantFunctorialConstruction). Hence, the role of Algebras(QQ).TensorProducts() is solely to provide mathematical information and algorithms which are relevant to tensor product of algebras.

Those are implemented in the nested class TensorProducts of Algebras(QQ). This nested class is itself a subclass of TensorProductsCategory.

TESTS:

sage: TestSuite(tensor).run()

sage.categories.tensor.TensorProducts(self)

INPUT:

• self – a subcategory of ModulesWithBasis(...)

Returns the category of objects constructed as tensor products of objects of self.

See TensorProductFunctor for more information

EXAMPLES:

sage: ModulesWithBasis(QQ).TensorProducts()
Category of tensor products of modules with basis over Rational Field

class sage.categories.tensor.TensorProductsCategory(category, *args)

Bases: sage.categories.covariant_functorial_construction.CovariantConstructionCategory

An abstract base class for all TensorProducts’s categories

TESTS:

sage: C = ModulesWithBasis(QQ).TensorProducts()
sage: C
Category of tensor products of modules with basis over Rational Field
sage: C.base_category()
Category of modules with basis over Rational Field
sage: latex(C)
\mathbf{TensorProducts}(\mathbf{ModulesWithBasis}_{\Bold{Q}})
sage: TestSuite(C).run()

TensorProducts()

Returns the category of tensor products of objects of self

By associativity of tensor products, this is self (a tensor product of tensor products of ‘s is a tensor product of ‘s)

EXAMPLES:

sage: ModulesWithBasis(QQ).TensorProducts().TensorProducts()
Category of tensor products of modules with basis over Rational Field

sage.categories.tensor.tensor

The tensor product functorial construction

See TensorProductFunctor for more information

EXAMPLES:

sage: tensor
The tensor functorial construction