the wedge product) in homotopy A few of the above products are examples of the general notion of an internal product in a monoidal category; the rest are describable by the general notion of a product in category theory. Products in category theory All of the previous examples are special cases or examples of the general notion of a product. For the general treatment of the concept of a product, see product (category theory), which describes how to combine two objects of some kind to create an object, possibly of a different kind. But also, in category theory, one has: the fiber product or pullback, the product category, a category that is the product of categories. the ultraproduct, in model theory. the internal product of a monoidal category, which captures the essence of a tensor product. Other products A function's product integral (as a continuous equivalent to the product of a sequence or as the multiplicative version of the normal/standard/additive integral. The product integral is also known as "continuous product" or "multiplical". Complex multiplication, a theory of elliptic curves. See also Indefinite product Infinite product Notes References Bibliography Multiplication