join - lub (least upper bound).
meet - glb (greatest lower bound).

R^+  - smallest transitive clojure of relation R
R^*  - smallest reflexive transitive clojure of relation R

Ex Ru - 525 - 592
285(315) 21.2    - Finite and Infinite Types (tree notation)
294      21.5.10 - Pred, Reachable
392      26.2    - Kernel F-sub
395              - Full F-sub