Questions tagged [cubic-reciprocity]
Use this tag for questions about theorems in number theory that state conditions under which the congruence x³ ≡ p (mod q) is solvable.
29 questions
2 votes
1 answer
98 views
Weak cubic reciprocity in Diamond and Shurman
In Diamond and Shurman, I am trying to understand the weak form of cubic reciprocity in section 4.11 - how it comes from the more standard version. In the following $A$ is the Eisenstein integers, and ...
4 votes
0 answers
182 views
A proof using cubic reciprocity.
I'm trying to solve this problem: $$n!+n(n+1)/2=m^3.$$ If $n+1=p$ is prime this leads to $2(n-1)!+p=a^3.$ If $p$ is a cubic non-residue for some $q<p$ the equation has no solution. This seems to ...
1 vote
1 answer
118 views
Cubic Character of 2
Proposition: If $p \equiv 1 \pmod 3$, then $x^3 \equiv 2 \pmod p$ is solvable if and only if there are integers $C$ and $D$ such that $p=C^2 + 27 D^2$. Proof: If $x^3 \equiv 2 \pmod p$ is solvable, ...
3 votes
0 answers
314 views
Applications of Langlands for GLn Explicit reciprocity laws other than elliptic curves
Is there any explicit application of Langlands conjecture for $\mathrm{GL}(n)$ for $n \ge 3$, to get some reciprocity laws for higher dimensional varieties or higher genus curves? I've never found ...
4 votes
1 answer
163 views
Cubic non-residue calculation
I am currently studying Cubic residue characters from Kenneth Ireland and Michael Rosen's "A Classical Introduction to Modern Number Theory", and this is the definition given in the book: If ...
3 votes
0 answers
135 views
When is $2023$ a cubic residue residue mod $p$?
When is $2023$ a cubic residue residue mod $p$ that is $1\pmod{3}$? I do know about quadratic reciprocity, since $x^{2}\equiv2023\pmod{p}$ is only solvable if $p\equiv\pm1\pm3\pm9\pmod{28}$, but I don’...
3 votes
2 answers
654 views
Is there any way to predict the largest number of consecutive quadratic or cubic residues modulo prime $p$?
We all know that $a$ is a quadratic residue modulo $p$ if and only if $a^{(p-1)/2} \equiv 1 \pmod p$, also $a$ is a cubic residue modulo $p$ if and only if $a^{(p-1)/3} \equiv 1 \pmod p$. Now, for a ...
0 votes
1 answer
78 views
Are primes of the form $6k+1$ a cube modulo $n$, if $3\nmid n$ and none of the prime factors of $n$ is of the form $6k+ 1$?
I wonder if we can assume the following statement to be true in general: Let $p$ be a prime of the form $6k+1$ and $n<p$ a natural number less than $p$. If $3$ does not divide $n$ and none of the ...
1 vote
1 answer
98 views
If $x^3+2y^3=p$ has a solution over positive integers, then is it unique?
I am trying to prove that for an odd prime $p$, if $x^3+2y^3=p$ has a solution over positive integers, then it is unique. My work, Assume $(x,y)=(a,b)$ and $(x,y)=(c,d)$ are different solutions. $\...
0 votes
3 answers
469 views
Perfect squares and cubes in quadratic number fields
Suppose we are given a quadratic number field $\mathbb{Q}(\sqrt{d})$, for some integer $d$ which is not a perfect square. I wish to study when is an element $\alpha \in \mathbb{Q}(\sqrt{d})$ a perfect ...
1 vote
1 answer
190 views
Extending the Supplement of Eisenstein Reciprocity
One of the supplements of Eisenstein Reciprocity states the following: Supplement: If $m$ is an odd prime and $a$ is a rational integer relatively prime to $m$, then $\left(\frac{1-\zeta_m}{a }\right)...
0 votes
0 answers
107 views
Reference Request: Cubic and Biquadratic Reciprocity Law
I want to read about the Cubic and Biquadratic Reciprocity Laws after learning the Quadratic Reciprocity Law. I already know about Franz Lemmermeyer's book "Reciprocity Laws", but I think this is a ...
0 votes
1 answer
187 views
Are cube roots evenly distributed modulo primes?
Are the cube roots of two integers chosen from a uniform distribution between $1$ and $p-1$ inclusive, $p$ prime, essentially evenly distributed? Note that I will use a $p$ such that $p$ is not ...
2 votes
0 answers
146 views
Applications of higher order reciprocity laws
I'm currently studying quartic & cubic residues and their reciprocity laws, and would like to know of any real world applications to finding the values of their respective residue symbols. I ...
1 vote
0 answers
64 views
Quadratic and Cubic Fractional Residues
Is there any method to find out the characterization of all primes $p$ such that $\frac{a}{b}$ is a quadratic residue modulo $p$ such that $a$ and $b$ are primes? Is there any method to do the same ...