Source : Free On-Line Dictionary of Computing

antichain
     
         A subset S of a {partially ordered set} P is an
        antichain if,
     
         for all x, y in S,  x <= y  =>  x = y
     
        I.e. no two different elements are related.
     
        ("<=" is written in {LaTeX} as {\subseteq}).
     
        (1995-02-03)