Zero divisors in Zp where p is prime

In summary, the conversation is about finding zero divisors in the ring Z17. The attempt at a solution involves multiplying 17 and 17 and determining that there are no zero divisors. However, there is some discussion about whether or not this is a clear explanation and if it has to do with 17 being a prime number. The conclusion is that in order for a*b to be divisible by 17, both a and b must be in Z17 and therefore, if a*b does not give 0 in Z17, it is not a zero divisor.
  • #1
sarah77
27
0

Homework Statement



Find all zero divisors of the ring Z17

Homework Equations



Are there any zero divisors of the ring Z17?

The Attempt at a Solution



I multiplied 17*17=289...that is only divisible by 17, so I do not think there are any zero divisors...am I missing something?
 
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  • #2
No, there aren't any zero divisors in Z_17. But I'm not sure that 17*17=289 which is only divisible by 17 is a clear statement of the reason why not. If a*b is divisible by 17 then can a and b both not be divisible by 17? Why not?
 
  • #3
Both a and b have to be in Z17, so if a*b does not give 0 in Z17, it is not a zero divider, right?
 
  • #4
sarah77 said:
Both a and b have to be in Z17, so if a*b does not give 0 in Z17, it is not a zero divider, right?

Sure, that's the definition. Do you think this might have anything to do with 17 being a prime number?
 
  • #5
Yes, but I wanted to explain it using a and b
 
  • #6
sarah77 said:
Yes, but I wanted to explain it using a and b

If a*b=0 mod 17 then they are zero divisors. That means a*b is divisible by 17. Is that possible without a or b being divisible by 17?
 
  • #7
Thank you!
 

1. What are zero divisors in Zp where p is prime?

Zero divisors in Zp where p is prime refer to elements in the ring of integers modulo p that, when multiplied by any other element, result in a product of 0. In other words, these elements have no multiplicative inverse in the ring.

2. How do you identify zero divisors in Zp?

To identify zero divisors in Zp, you can check if the given element is relatively prime to p. If the greatest common divisor of the element and p is not equal to 1, then the element is a zero divisor. Another way to identify zero divisors is to check if the element is congruent to 0 modulo p.

3. Why is it important to study zero divisors in Zp?

Studying zero divisors in Zp is important because it helps us understand the structure of the ring of integers modulo p. It also has applications in cryptography and coding theory, where zero divisors can be used to generate error-correcting codes.

4. How many zero divisors are there in Zp?

The number of zero divisors in Zp is equal to the number of integers less than p that are not relatively prime to p. In other words, the number of zero divisors in Zp is equal to p - 1 minus the number of prime factors of p - 1.

5. Can a prime number be a zero divisor in Zp?

No, a prime number cannot be a zero divisor in Zp. This is because a prime number is only divisible by 1 and itself, and in the ring of integers modulo p, every element has a unique multiplicative inverse except for 0. Therefore, a prime number cannot be multiplied by any other element to result in a product of 0.

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