Thursday, August 25, 2011

Finite and Infinite Sets

1.       So, we understand what a set is. It contains something, bounded by some rules.
2.       Let us talk about the nature of the rules that define a set.
3.       First thing that we have till now noticed obviously (I am not sure how much obvious it is!) is that these rules must help us to decide with certainty whether something will belong to the set or not.
4.       Next thing about the rules is that how many things they allow in the set.
5.       If they allow a number of things that you can count or in advance know how many things will belong to the set, then it is a finite set.
6.       If the rules allow a number that you can’t count or you know that there are always more, as you continuously can find more and more things to be put in the set, it is then an infinite set.
7.       That much said it is really difficult to swallow the fact that how can someone make a rule that he/she may not know exactly how many things to put in the set?
8.       Well, if you think you can only think of the rules that will give you some finite set then you are in your senses and have not gone crazy! J
9.       But, take the example of a crazy person who wants to make a set with the sand particles from a sea beach!
10.   He clearly knows what to put in this set, and he is also sure he is going to find many things to put in his set. The difficulty is he can’t ever tell in his lifetime that how many sand particles will finally be there in his set!
11.   So there can be some crazy rules possible, and to allow for this craziness, Mathematicians (who are equally crazy and take a certain happiness in making others crazy too J) created this concept of infinite set!
12.       So, clear about finite and infinite set. Now, where should the empty set be classified, finite or infinite?
13.       What you know about empty set is that it has nothing, you are certain about that it contains zero elements. That is you know how many things it has, it has zero things! That’s why it is also a finite set.

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