Extending the Fundamental Theorem of Arithmetic to the rationals

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SUMMARY

The discussion centers on the extension of the Fundamental Theorem of Arithmetic (FTA) to positive rational numbers. Participants argue that while any positive rational number can be expressed as a product of primes with integer exponents, the uniqueness of such representations is questionable. The consensus is that the FTA applies to integers but cannot be generalized to rational numbers due to the absence of prime elements in fields like the rationals. The theorem's application to rational numbers is viewed as merely reiterating the FTA for numerators and denominators rather than establishing a new theorem.

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  • Understanding of the Fundamental Theorem of Arithmetic (FTA)
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  • Familiarity with rational numbers and their representation
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  • #31
Warp said:
I am not sure about the uniqueness, however. Could two different combinations of integers produce the same rational number?
Of course they can \frac{1}{2} and \frac{17}{34} represent the same rational number.

Rationals do not have a unique representation. Every rational number is a member of an equivalence class of combinations of integers.
 
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  • #32
Svein said:
Of course they can \frac{1}{2} and \frac{17}{34} represent the same rational number.

Rationals do not have a unique representation.
But they have a unique reduced form to lowest terms, p/q where GCD(p,q)=1. Then both p and q can be factored uniquely into primes where p and q have no common primes.
 
  • #33
FactChecker said:
But they have a unique reduced form to lowest terms, p/q where GCD(p,q)=1. Then both p and q can be factored uniquely into primes where p and q have no common primes.
The crucial point is the title. The word extension suggests a form of generalization, which it is not. You can't extend from ring to field. No way.
 
  • #34
fresh_42 said:
The crucial point is the title. The word extension suggests a form of generalization, which it is not. You can't extend from ring to field. No way.
There are some formally defined uses of the word "extension", but extending a theorem is not one of those.
In any case, the original question has probably been answered.
 
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  • #35
fresh_42 said:
The crucial point is the title. The word extension suggests a form of generalization, which it is not. You can't extend from ring to field. No way.
It is a generalization in the sense that it is a correct statement which includes unique factorization in the integers as a special case, not in the sense that it deals with prime elements in ##\mathbb{Q}.##
 
  • #36
An application of FTA is something basically different than an extension of FTA.

This is logically relevant as it is algebraically. To throw it all in one pot teaches the wrong motivations. A true statement isn't the same thing as a true classification. All posts above thought to an end would mean: Let's gather all theorems, list them in a book and call it: True. I cannot see how this is doing anyone a favor.
 
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