meaning of least fixed point
1. least fixed point A function f may have many fixed points x such that f x = x. For example, any value is a fixed point of the identity function, x . x. If f is recursive, we can represent it as f = fix F where F is some higher-order function and fix F = F fix F. The standard denotational semantics of f is then given by the least fixed point of F. This is the least upper bound of the infinite sequence the ascending Kleene chain obtained by repeatedly applying F to the totally undefined value, bottom. I. e. fix F = LUB bottom, F bottom, F F bottom, . . . . The least fixed point is guaranteed to exist for a continuous function over a cpo. least recently used operating systems LRU A rule used in a paging system which selects a page to be paged out if it has been used read or written less recently than any other page. The same rule may also be used in a cache to select which cache entry to flush. This rule is based on temporal locality - the observation that, in general, the page or cache entry which has not been accessed for longest is least likely to be accessed in the near future.
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