Re: Objects and Relations

"Neo" <neo55592_at_hotmail.com> wrote in news:1170294887.106812.161460_at_a34g2000cwb.googlegroups.com:

> show how to derived it from unordered sets?
>

The formation rule of the Kuratowski pair is (a,b) def= { {a}, {a, b} }. When one has the ordered pair, one can formate an ordered tuple by mapping one-to-one an initial fragment of the natural numbers onto a finite set of interest, for example {1,2,3} -> {m, j, a} gives { (1,m), (2,j), (3, a)}. It can be understood like (m, j, a), a tuple or a list, it is the same thing. This is all very simple and very well known and called 'indexing'. There are other methods of express a tuple with sets, but it is the most simple.

[Quoted] If you do not understand a rule so simple, my fear is that I can not help any more, I am sorry.

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Tegi