Transfors between 2-categories
Morphisms in 2-categories
Structures in 2-categories
Limits in 2-categories
Structures on 2-categories
Higher category theory
higher category theory
Extra properties and structure
In a 2-category (and more generally in higher category theory) 2-morphisms have a composition along the 1-morphisms that they go between.
& \nearrow &\Downarrow& \searrow
x &&\to&& y
& \searrow &\Downarrow& \nearrow
This is in contrast to the other composition operation, along objects, which is called horizontal composition.
Created on September 9, 2010 08:12:37
by Urs Schreiber