Prove Polynomials of Degree 1, 2 & 4 Have Roots in Z_2[x]/(x^4+x+1)

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Discussion Overview

The discussion revolves around proving that every polynomial of degree 1, 2, and 4 in Z_2[x] has a root in the quotient ring Z_2[x]/(x^4+x+1). Participants explore methods and considerations for addressing this problem, including specific cases and irreducibility.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant suggests using exhaustion due to the limited number of cases, implying that the degree 1 case is straightforward.
  • Another participant identifies that the degree 2 case is generally obvious except for the irreducible polynomial x^2+x+1, indicating a need to find a solution for that specific case.
  • A participant expresses dissatisfaction with their approach, suggesting that they are not fully confident in their reasoning regarding the irreducible cases for degree 4 polynomials.
  • One participant encourages examining the irreducible cases to derive a general condition that explains why polynomials of degrees 1, 2, and 4 have roots, while also noting the existence of a degree 3 polynomial that does not.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the approach to proving the claim, with some expressing confidence in certain cases while others highlight the need for further exploration of irreducible polynomials.

Contextual Notes

Participants mention specific irreducible polynomials and the implications of their properties, but do not resolve the mathematical steps or conditions necessary for a complete proof.

Who May Find This Useful

This discussion may be useful for those interested in polynomial algebra, particularly in the context of finite fields and quotient rings.

whodoo
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I want to show that every polynomial of degree 1, 2 and 4 in Z_2[x] has a root in Z_2[x]/(x^4+x+1). Any ideas?

Ps. How can I use latex commands in my posts?
 
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You can just do it by exhaustion. There are very few cases to think about (and if you have to start thinking about the case deg=1 then you're missing something).

LaTeX is explained in the introduction to LaTeX thread (probably in physics): just look around.
 
Okey, something like this?
The case deg 1 is obvious. The case 2 is obvious except for the irreducible x^2+x+1, where I can find a solution. Degree 4 is obvious except for the irreducible cases which I can try?

Im not really satsified with this solution.
 
Why not? Have you actually tried to look at the irreducible casees? If you do you might figure out what a general condition would be, and why the degs 1,2,4 polys all satisfyit (and presumably why there is a deg 3 poly that doesn't). You won't figure out a general criterion just by pulling it out of thin air. You look at cases where it is true, where it isn't and figure out what quantifies the difference. That's how you do maths.
 

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