von Neumann integer
<mathematics> 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)