Abstract prime factorization proof

In summary: Then compare the exponents in the two factorizations.In summary, an integer a>1 is a square if and only if every exponent in its prime factorization is even. To prove this, we have to show that if a is a square, then every exponent in its prime factorization is even, and if every exponent in a's prime factorization is even, then a is a square. To do this, we can use the definition of prime factorization and compare the exponents in the prime factorization of a and n^2.
  • #1
kathrynag
598
0

Homework Statement


A positive integer a is called a square if a=n^2 for some n in Z. Show that the integer a>1 is a square iff every exponent in its prime factorization is even.



Homework Equations





The Attempt at a Solution


Well, I know a=p1^a1p2^a2...pn^a^n is the definition of prime factorization.
We let p=2n because any even number squared is an even numbers.
Not sure how to continue.
 
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  • #2
I keep trying to work on this one on I'm getting nowhere. Am I on the right track or does anyone have a suggestion?
 
  • #3
It's not an even number; the exponents are even.

So in the prime factorization of a, [itex]{a_1,a_2,...,a_n}[/itex] are even. Now what does that mean about the square root of a?
 
  • #4
@kathrynag,

When you have an "iff" problem, you really have to solve two problems. Here's a restatement of the problem to make this more clear:
Let a > 1 be an integer.

1. Assume that a is a square. Prove that every exponent in its prime factorization is even.

2. Assume that every exponent in a's prime factorization is even. Prove that a is a square.

Does this help?
 
  • #5
Petek said:
@kathrynag,

When you have an "iff" problem, you really have to solve two problems. Here's a restatement of the problem to make this more clear:
Let a > 1 be an integer.

1. Assume that a is a square. Prove that every exponent in its prime factorization is even.

2. Assume that every exponent in a's prime factorization is even. Prove that a is a square.

Does this help?
Yeah, that does help. I fell better about the 2nd part of the proof.
The first part still worries me.
Assume n is a square. Then we have a=n^2
That's about as far as I get with that one.
I know what I need to prove, but it's getting there.
n^2=p1^a1p2^a2...pn^an
 
  • #6
hgfalling said:
It's not an even number; the exponents are even.

So in the prime factorization of a, [itex]{a_1,a_2,...,a_n}[/itex] are even. Now what does that mean about the square root of a?

It is also even.
 
  • #7
No. Consider 9. Its prime factorization is [itex] 3^2 [/itex]. Therefore it satisfies the rules of your problem. But it's not even, nor is it the square of an even number.
 
  • #8
kathrynag said:
Yeah, that does help. I fell better about the 2nd part of the proof.
The first part still worries me.
Assume n is a square. Then we have a=n^2
That's about as far as I get with that one.
I know what I need to prove, but it's getting there.
n^2=p1^a1p2^a2...pn^an

Hint: Write out the prime factorization for n and then use that to come up with another prime factorization for n^2.
 

FAQ: Abstract prime factorization proof

What is abstract prime factorization proof?

Abstract prime factorization proof is a mathematical method used to prove that a given number is prime. It involves breaking down the number into its prime factors and showing that there are no other factors besides the number itself and 1.

How is abstract prime factorization proof different from regular prime factorization?

Regular prime factorization involves finding the prime factors of a number using a specific algorithm, whereas abstract prime factorization proof is a more general method that can be applied to any number without the use of a specific algorithm.

Why is abstract prime factorization proof important?

Abstract prime factorization proof is important because it allows us to prove the primality of any number, regardless of its size. This is useful in many fields of mathematics and has practical applications in cryptography and computer science.

What are the steps involved in abstract prime factorization proof?

The steps involved in abstract prime factorization proof are: 1) Write the number as a product of its prime factors; 2) Show that there are no other factors besides the number itself and 1; 3) Use the Fundamental Theorem of Arithmetic to prove that the number is prime.

What are some common misconceptions about abstract prime factorization proof?

One common misconception is that abstract prime factorization proof only works for small numbers, when in fact it can be applied to any number. Another misconception is that it is a complicated and time-consuming process, when in reality it can be done efficiently with the right techniques.

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