category
131Category of metric spaces — The category Met, first considered by Isbell (1964), has metric spaces as objects and metric maps or short maps as morphisms. This is a category because the composition of two metric maps is again metric.The monomorphisms in Met are the injective …
132Category of elements — In category theory, for every presheaf P inhat C := mathbf{Set}^{C^{op the category of elements mathbf{El}(P) of P is the category defined as follows: * its objects are pairs (A,a) where A is an object of C and ain P(A), * its morphisms (A,a) o… …
