Finding the order of a quotient field

In summary, the order of ##\mathbb{Z}_3 [x] / \langle x^2 + 2x + 2 \rangle## and ##\mathbb{Z}_3 [x] / \langle x^2 + x + 2 \rangle## is 27. This is because both consist of elements of the forms ##ax^2 + bx + c + \langle x^2 + 2x + 2 \rangle## or ##ax^2 + bx + c + \langle x^2 + x + 2 \rangle##, with three choices for the coefficients a, b, c, resulting in 3^3 = 27 possible combinations. Additionally, it is
  • #1
Mr Davis 97
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Homework Statement


Find the order of ##\mathbb{Z}_3 [x] / \langle x^2 + 2x + 2 \rangle ## and ##\mathbb{Z}_3 [x] / \langle x^2 + x + 2 \rangle ##

Homework Equations

The Attempt at a Solution


Is there an efficient method for doing this? Is the answer 27 for both? It would seem that both of these consist of elements of the forms ##ax^2 + bx + c + \langle x^2 + 2x + 2 \rangle## or ##ax^2 + bx + c + \langle x^2 + x + 2 \rangle##, and there are three choices for the coefficients a, b, c, so ##3^3 = 27##
 
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  • #2
Mr Davis 97 said:
It would seem that both of these consist of elements of the forms ##ax^2 + bx + c + \langle x^2 + 2x + 2 \rangle## or ##ax^2 + bx + c + \langle x^2 + x + 2 \rangle##
Are you sure? How did you derive this?
 
  • #3
andrewkirk said:
Are you sure? How did you derive this?
Well I am not sure. But my intuition tells me that all higher order polynomials can be written as lower powers by using the ##x^2 = -2x -2## or ##x^2 = -x -2##
 
  • #4
Mr Davis 97 said:
Well I am not sure. But my intuition tells me that all higher order polynomials can be written as lower powers by using the ##x^2 = -2x -2## or ##x^2 = -x -2##
What is the maximum possible order of the remainder polynomial one gets from dividing a polynomial by ##x^22+2x+2##?
 

1. How do you find the order of a quotient field?

To find the order of a quotient field, you must first identify the prime factors of the numerator and denominator of the quotient. Then, find the highest power of each prime factor that is present in the numerator but not in the denominator. The order of the quotient field will be the product of these powers.

2. Can the order of a quotient field be infinite?

Yes, the order of a quotient field can be infinite. This occurs when there are no common prime factors between the numerator and denominator of the quotient. In this case, the order will be the product of infinitely many ones, resulting in an infinite order.

3. What is the significance of finding the order of a quotient field?

The order of a quotient field is significant because it tells us the number of elements in the field. This information is important in many mathematical applications, such as group theory and number theory.

4. Can the order of a quotient field change?

No, the order of a quotient field cannot change. It is a property of the field itself and is determined by the prime factors of the numerator and denominator of the quotient.

5. Are there any shortcuts for finding the order of a quotient field?

Yes, there are some shortcuts that can be used to find the order of a quotient field more quickly. One method is to use the Euclidean algorithm to find the greatest common divisor of the numerator and denominator, and then use this divisor to simplify the quotient. Another method is to use the Chinese remainder theorem if the numerator and denominator have relatively prime factors.

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