- #1
gatztopher
- 26
- 0
Hey all, I have a very basic question. Kuratowski's definition of ordered pairs,
(a, b)K := {{a}, {a, b}}
is not clicking for me. Part of the problem is I haven't had a serious look at naive set theory since high school, but after reading the webs for a couple of hours, things are good for me except for this one piece.
My points of confusion:
1. Why is an ordered pair defined in terms of unordered pairs? Doesn't {{a}, {a, b}} = {{a, b}, {a}} = {{b, a}, {a}}, and if so, how does this in any way become ordered?
2. How was this definition arrived at? Where I've looked, it's usually just stated without any context for why or how it emerged.
I've long been a fan of physicsforum, thanks for your help!
(a, b)K := {{a}, {a, b}}
is not clicking for me. Part of the problem is I haven't had a serious look at naive set theory since high school, but after reading the webs for a couple of hours, things are good for me except for this one piece.
My points of confusion:
1. Why is an ordered pair defined in terms of unordered pairs? Doesn't {{a}, {a, b}} = {{a, b}, {a}} = {{b, a}, {a}}, and if so, how does this in any way become ordered?
2. How was this definition arrived at? Where I've looked, it's usually just stated without any context for why or how it emerged.
I've long been a fan of physicsforum, thanks for your help!