Scott-closed
Scott-closed
(1) If Y is a subset of S and Y is directed then lub Y is inS and
(2) If y <= s in S then y is in S.
I.e. a Scott-closed set contains the lubs of its directedsubsets and anything less than any element. (2) says that Sis downward closed (or left closed).
("<=" is written in LaTeX as \\sqsubseteq).