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Old 2007-02-24, 17:45   #1
davar55
 
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Default Define a Prime

Can you define prime numbers over the non-negative
integers without any explicit reference to 0 or 1 or 2
or any other specific integer?
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Old 2007-02-24, 17:52   #2
Orgasmic Troll
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Quote:
Originally Posted by davar55 View Post
Can you define prime numbers over the non-negative
integers without any explicit reference to 0 or 1 or 2
or any other specific integer?
non-negative integers that are only divisible by themselves and the units in the ring of integers
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Old 2007-02-24, 17:52   #3
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An integer so that any product equal to the integer must involve the integer itself, units, and nothing else.

Alex
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Old 2007-02-24, 18:00   #4
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Quote:
Originally Posted by davar55 View Post
Can you define prime numbers over the non-negative
integers without any explicit reference to 0 or 1 or 2
or any other specific integer?
Let (p,q) be non-negative integers such that N=p*q and p>q

If for all (p,q) p=N, then N is prime.


Pau

Last fiddled with by xilman on 2007-02-24 at 18:01 Reason: Add spoiler tags
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Old 2007-02-24, 20:19   #5
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Here's another try:

A positive integer p is prime if and only if the only solutions to the equations p = a*b = c*d occur when a is not equal to b and a = c and b = d or a = d and b = c. (I almost said that the equation p = a*b has exactly two solutions (a,b) where a and b are positive integers, but then realized that I was violating the terms of the problem!)
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Old 2007-02-24, 22:23   #6
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A prime number (or a prime) is a natural number that has exactly two (distinct) natural number divisors, which are (4 - 3) and the prime number itself.
Hooray for loopholes!
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Old 2007-02-24, 23:04   #7
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Quote:
Originally Posted by Mini-Geek View Post
that has exactly two
Rule violation. Five yards penalty.

Alex
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Old 2007-02-24, 23:34   #8
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Quote:
Originally Posted by TravisT View Post
non-negative integers that are only divisible by themselves and the units in the ring of integers
Counter-example.

3 is a non-negative integer

3 is divisible by itself --- meets your definition

3 is divisible by 1, a unit in the ring of integers --- meets your definition

3 is divisible by -1, a unit in the ring of integers --- meets your definition

-3 is an element of the ring of integers

3 is divisible by -3


Therefore, according to your definition, 3 is not a prime.



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Old 2007-02-24, 23:52   #9
akruppa
 
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Same problem with my definition. Let's try

An integer so that any product equal to the integer must involve the integer itself or one of its associates, any number of units, and nothing else.

Alex
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Old 2007-02-25, 00:35   #10
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Quote:
Originally Posted by akruppa View Post
Rule violation. Five yards penalty.

Alex
Ok, fine, here's the updated version:

A prime number (or a prime) is a natural number that has exactly (5 - 3) (distinct) natural number divisors, which are (4 - 3) and the prime number itself.
Hooray for loopholes!

Last fiddled with by Mini-Geek on 2007-02-25 at 00:35
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Old 2007-02-25, 01:29   #11
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One may try to invent something analytical from
http://mathworld.wolfram.com/LandausFormula.html

:-)
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