Algebra help - primitive roots and minimal polynomials

In summary, the first question asks for a primitive root in \mathbb{F}_3[x]/(x^2+1). The student is unable to find one, so they need to look for a root that will give 1 when taking the power of the order of the polynomial. They are not sure if this is the same as a primitive root, but they are still lost. For the second question, the student needs to find the minimal polynomial p(x) of ̓ldeβ in ̓mathbb{F}_3[x]. They are able to find this polynomial and show that F3[x]/(x^2+1) is is
  • #1
cooljosh2k2
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Homework Statement



(a) Find a primitive root β of F3[x]/(x^2 + 1).
(b) Find the minimal polynomial p(x) of β in F3[x].
(c) Show that F3[x]/(x^2 + 1) is isomorphic to F3[x]/(p(x)).


The Attempt at a Solution



I am completely lost on this one :confused:
 
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  • #2
So for the first one, you need to find a primitive root in [tex]\mathbb{F}_3[x]/(x^2+1)[/tex]
Can you tell us what a primitive root is?
Can you find any root (not just primitive) in our field? To find this, take an arbitrary element a+bx in our field. Can you find a, b and n such that [tex](a+bx)^n=1[/tex]?
 
  • #3
From what i understand, a primitive root is a value that when taking to the power of the order of the polynomial, you will get 1 (mod 3 for this example) I don't know if this is right, but i get x^2+1 as a primitive root. Does that make sense. The order of the polynomial is 2, so (x^2+1)^2 = 1
 
  • #4
Wow, I have an entirely different definition of primitive root...
I have this: Let F be a field, then a nth root is an element x in F such that [tex]x^n=1[/tex] for some [tex]n>0[/tex]. The nth root x is called primitive if there is no k<n such that [tex]x^k=1[/tex].

Does this make any sense to you? Or do you understand something completely different in the term root?
 
  • #5
That makes sense, but from what i thought i understood, the n is usually the order (or degree) of the polynomial. But i might be wrong.
 
  • #6
I don't really understand what polynomials have to do with this. The only thing I can image is that a nth root of unity is a root of the polynomial [tex]X^n-1[/tex].

Can you give me the exact definition in your course? I really want to know if we're talking about thesame thing here...
 

FAQ: Algebra help - primitive roots and minimal polynomials

What is a primitive root in algebra?

A primitive root is an integer that is relatively prime to a given modulus and generates all of the integers in a set modulo the modulus. In other words, it is a number that, when raised to different powers, produces all of the possible remainders when divided by the modulus.

Why are primitive roots important in algebra?

Primitive roots play a crucial role in number theory and algebra. They are used in cryptographic algorithms, primality testing, and constructing finite fields. They also have applications in other areas of mathematics, such as group theory and combinatorics.

How do you find primitive roots in algebra?

To find primitive roots, you first need to determine the totient function of the given modulus. Then, you can use this value to find potential primitive roots by checking which numbers have the property that their order (smallest power that produces 1 when raised to it) is equal to the totient function. Finally, you can test these potential primitive roots to see if they indeed generate all of the integers modulo the given modulus.

What is a minimal polynomial in algebra?

A minimal polynomial is the smallest polynomial with integer coefficients that has a given number as a root. In other words, it is the polynomial of least degree that has a given number as a solution.

Why are minimal polynomials important in algebra?

Minimal polynomials have various applications in algebra, particularly in fields such as linear algebra and Galois theory. They are used to determine the algebraic properties of a given number, such as its degree and field of definition. They also provide a way to represent algebraic numbers in a concise form.

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