Processing math: 100%

Sunday, March 3, 2013

Fibred categories of subsets and slices over Set

Each (function f:XY) in Set (the large 1-category of small sets)
generates (the following diagram of categories and functors) in CAT (the very large 2-category of large categories).
Note: below (the diagram in CAT) we show (the function f:XY in Set) that generates it. SetXf=f!ff=fSetYfunctors between categories of oversetsσXiXσYiYreflections of oversets (supersets) into subsetsSub(X)f=f!f1f=fSub(Y)order-preserving maps between posets of subsetsXfYan arrow (function) in Set Each horizontal triple of arrows, upper and lower, is an adjoint triple, i.e. an adjoint string of length 3.

No comments:

Post a Comment

MathJax 2.7.9