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--- uf:flock [2008/09/12 15:31] – tvcutsem
+++ uf:flock [2009/11/18 13:53] (current) – elisag
@@ Line 1: / Line 1: @@
-A flock is a list of [[Flockr]]s as generated by means of [[Proximities|a proximity function]].
+====== Flock ======
-The list changes dynamically as the input to the proximity function changes (e.g. because of buddies joining, leaving, updating their profile, being added or deleted).
+A flock is a list of [[Flockr]]s defined in terms of [[Proximities | a characteristic function ]] that determines which users belong to the flock.
-In other words, while the proximity function can be regarded as an "intensional" representation of a group of friends, the flock is the "extensional" representation of that group. For example, if ''f'' is a flock of "all of my friends who are older than 25" (an intensional description), and the friend list is "[Alice (26), Bob (22), Carol (24)]", then the flock contains only Alice (an extensional representation of the group)
+The list changes dynamically as the input to the characteristic function changes (e.g. because of buddies joining, leaving, updating their profile, being added or deleted).
+In other words, while the characteristic function can be regarded as an "intensional" representation of a group of friends, the flock is the "extensional" representation of that group. For example, if ''f'' is a flock of "all of my friends who are older than 25" (an intensional description), and the friend list is "[Alice (26), Bob (22), Carol (24)]", then the flock contains only Alice (an extensional representation of the group)
 === Implementation ===
 Conceptually, a flock is a list of flockrs. Technically, a flock is implemented as a list of profiles. From the profiles, the flock can acquire the flockr's unique username. Given the username, the flock can acquire a far ref to the flockr via its own "owner" flockr.