資料來源 : Free On-Line Dictionary of Computing

von Neumann integer
     
         A {finite} {von Neumann ordinal}.
     
        The von Neumann integer N is a {finite} set with N elements
        which are the von Neumann integers 0 to N-1.  Thus
     
        	0 = {}		= {}
        	1 = {0}		= {{}}
        	2 = {0, 1}	= {{}, {{}}}
        	3 = {0, 1, 2}	= {{}, {{}}, {{}, {{}}}}
        	...
     
        The set of von Neumann integers is {infinite}, even though
        each of its elements is finite.
     
        [Origin of name?]
     
        (1995-03-30)