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Subject: Re: Trying to explain O(1)(slightly off topic)

Author: Uri Blass

Date: 21:47:40 05/09/01

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On May 09, 2001 at 22:02:48, Jeremiah Penery wrote:

>On May 09, 2001 at 17:58:08, Uri Blass wrote:
>
>>The definition that I remember from university for O(1) is:
>>
>>f(n) is O(1) if there is a constant C such that |f(n)|<C for every finite n.
>>(|f(n)| is the absulute value of f(n)).
>>
>>We learn from this definition that if n is bounded then f(n) is O(1) because you
>>can choose C=1+max(|f(1)|,|f(2)...|f(n)|)
>>
>>An algorithm that help to solve only one problem that can be solved in a finite
>>time is always O(1) by this definition.
>>An algorithm that helps to solve a finite set of problems that everyone of them
>>can be solved in a finite time is also O(1) by this definition.
>>
>>1)If you look at the problems search to depth n in chess then there is only a
>>finite number of problems because searching to depth 9^(9^9) gives the same
>>result  as searching to depth 9^(9^9)+1 even without the 50 move rule.
>>
>>Conclusion:Searching to depth n in chess is O(1).
>
>No.  The idea behind O (for tree-searching algorithms) is to find out how much
>longer will it take to search from depth N to N+1.

In this case 0 seconds because if N is 9^(9^9) and you searched depth N you also
searched depth N+1.

I agree that chess is practically exponentional because you cannot go to the big
depthes that I described.

This is my last post in this discussion and the fact that I stop to post does
not say that I agree.

I stop to post only because of the fact that people complain that it is off
topic.

Uri



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