Skip to main content

All Questions

15 votes
2 answers
4k views

Irreducible polynomial modulo every prime?

There exist irreducible polynomials in $\mathbb{Z}[x]$ (e.g. $x^4-10x^2+1$) which are reducible modulo every prime $p$. (A proof can be found in J.S. Milne's Fields and Galois Theory, page 13.) This ...
wxu's user avatar
  • 6,711
68 votes
2 answers
33k views

Number of monic irreducible polynomials of prime degree $p$ over finite fields

Suppose $F$ is a field s.t $\left|F\right|=q$. Take $p$ to be some prime. How many monic irreducible polynomials of degree $p$ do exist over $F$? Thanks!
IBS's user avatar
  • 4,215
18 votes
4 answers
3k views

Reducibility over $\mathbb{Z}_2$?

I have seen that $x^{2}+x+1$ and $x^{4}+x+1$ are irreducible over $\mathbb{Z}_2$ and I thought a polynomial of the form $x^{2^m}+x+1$ for $m\ge3$ would be irreducible too. However using WolframAlpha, ...
boj54's user avatar
  • 335
17 votes
2 answers
3k views

Irreducible homogeneous polynomials of arbitrary degree

Suppose we have an algebraically closed field $F$ and $n+1$ variables $X_0, \dots, X_n$, where $n > 1$. Does there exist an irreducible homogeneous polynomial in these variables of degree $d$ for ...
Jean's user avatar
  • 173
57 votes
7 answers
30k views

Methods to see if a polynomial is irreducible

Given a polynomial over a field, what are the methods to see it is irreducible? Only two comes to my mind now. First is Eisenstein criterion. Another is that if a polynomial is irreducible mod p then ...
user avatar

15 30 50 per page
1
98 99 100 101
102