资料来源 : Free On-Line Dictionary of Computing

continuous function
     
        A function f : D -> E, where D and E are {cpo}s, is continuous
        if it is {monotonic} and
     
        	f (lub Z) = lub { f z | z in Z }
     
        for all {directed} sets Z in D.  In other words, the image of
        the lub is the lub of any directed image.
     
        All {additive} functions (functions which preserve all lubs)
        are continuous.  A continuous function has a {least fixed
        point} if its {domain} has a least element, {bottom} (i.e. it
        is a cpo or a "pointed cpo" depending on your definition of a
        cpo).  The {least fixed point} is
     
        	fix f = lub {f^n bottom | n = 0..infinity}
     
        (1994-11-30)