The natural monoidal structure on any category with finite (co)products. #
A category with a monoidal structure provided in this way is sometimes called a (co)cartesian category, although this is also sometimes used to mean a finitely complete category. (See https://ncatlab.org/nlab/show/cartesian+category.)
As this works with either products or coproducts, and sometimes we want to think of a different monoidal structure entirely, we don't set up either construct as an instance.
Implementation #
We had previously chosen to rely on HasTerminal
and HasBinaryProducts
instead of
HasBinaryProducts
, because we were later relying on the definitional form of the tensor product.
Now that has_limit
has been refactored to be a Prop
,
this issue is irrelevant and we could simplify the construction here.
See CategoryTheory.monoidalOfChosenFiniteProducts
for a variant of this construction
which allows specifying a particular choice of terminal object and binary products.
A category with a terminal object and binary products has a natural monoidal structure.
Equations
- CategoryTheory.monoidalOfHasFiniteProducts C = CategoryTheory.MonoidalCategory.ofTensorHom ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯
Instances For
The monoidal structure coming from finite products is symmetric.
Instances For
A category with an initial object and binary coproducts has a natural monoidal structure.
Equations
- CategoryTheory.monoidalOfHasFiniteCoproducts C = CategoryTheory.MonoidalCategory.ofTensorHom ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯
Instances For
The monoidal structure coming from finite coproducts is symmetric.
Instances For
Equations
- One or more equations did not get rendered due to their size.
Promote a finite products preserving functor to a monoidal functor between categories equipped with the monoidal category structure given by finite products.