-
1.
The existence or non-existence of Kan extensions and Kan lifts in the $2$-category $\boldsymbol {\mathsf{Rel}}$ (Section 9.2).
-
2.
The various kinds of constructions involving relations, such as graphs, domains, ranges, unions, intersections, products, converse relations, composition of relations, and collages (Section 9.3).
9 Constructions With Relations
This chapter contains some material about constructions with relations. Notably, we discuss and explore: