$n$th power residue conjecture











up vote
1
down vote

favorite












Let $left(dfrac{a}{p}right)_n$ be the $n$th power residue symbol such that when $a$ is an $n$th power residue $pmod p$, $left(dfrac{a}{p}right)_n=1$ otherwise $left(dfrac{a}{p}right)_n=zeta$. Let $f_n(x)$ be a defining polynomial for the $n$th cyclotomic field $K=mathbb{Q}(e^{2pi i/n})$. Suppose that there exists some integer $m$ such that $f_n(m)=0 pmod {n^2}$, and there are primes $p$ and $q$ such that $p=f_n(z)$ and $q=f_n(z+a)$. Then $left(dfrac{a}{p}right)_n = left(dfrac{a}{q}right)_n$. When $n=3$, this conjecture agrees with cubic reciprocity theorems. The same is true for $n=4$.



Here is an example of the conjecture for $n=5$:



$f_5(x)=x^4+5x^3+10x^2+25$ and $f_5(0)=0pmod {5^2}$



$a=3$, $p=f_5(1)=41$ and $q=f_5(1+a)=f_5(4)=761$ are both prime, thus



$left(dfrac{3}{41}right)_5 = left(dfrac{3}{761}right)_5$.



Since $3$ is a quintic residue $pmod {41}$, then it is also a quintic residue of $761$. In general, if $p=f_5(3a+1)$ is prime, then $3$ is a quintic residue $pmod p$.










share|cite|improve this question




















  • 2




    Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
    – KCd
    Nov 20 at 23:51












  • @KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
    – J. Linne
    Nov 21 at 7:32










  • For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
    – KCd
    Nov 21 at 11:24












  • @KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
    – J. Linne
    Nov 24 at 1:46

















up vote
1
down vote

favorite












Let $left(dfrac{a}{p}right)_n$ be the $n$th power residue symbol such that when $a$ is an $n$th power residue $pmod p$, $left(dfrac{a}{p}right)_n=1$ otherwise $left(dfrac{a}{p}right)_n=zeta$. Let $f_n(x)$ be a defining polynomial for the $n$th cyclotomic field $K=mathbb{Q}(e^{2pi i/n})$. Suppose that there exists some integer $m$ such that $f_n(m)=0 pmod {n^2}$, and there are primes $p$ and $q$ such that $p=f_n(z)$ and $q=f_n(z+a)$. Then $left(dfrac{a}{p}right)_n = left(dfrac{a}{q}right)_n$. When $n=3$, this conjecture agrees with cubic reciprocity theorems. The same is true for $n=4$.



Here is an example of the conjecture for $n=5$:



$f_5(x)=x^4+5x^3+10x^2+25$ and $f_5(0)=0pmod {5^2}$



$a=3$, $p=f_5(1)=41$ and $q=f_5(1+a)=f_5(4)=761$ are both prime, thus



$left(dfrac{3}{41}right)_5 = left(dfrac{3}{761}right)_5$.



Since $3$ is a quintic residue $pmod {41}$, then it is also a quintic residue of $761$. In general, if $p=f_5(3a+1)$ is prime, then $3$ is a quintic residue $pmod p$.










share|cite|improve this question




















  • 2




    Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
    – KCd
    Nov 20 at 23:51












  • @KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
    – J. Linne
    Nov 21 at 7:32










  • For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
    – KCd
    Nov 21 at 11:24












  • @KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
    – J. Linne
    Nov 24 at 1:46















up vote
1
down vote

favorite









up vote
1
down vote

favorite











Let $left(dfrac{a}{p}right)_n$ be the $n$th power residue symbol such that when $a$ is an $n$th power residue $pmod p$, $left(dfrac{a}{p}right)_n=1$ otherwise $left(dfrac{a}{p}right)_n=zeta$. Let $f_n(x)$ be a defining polynomial for the $n$th cyclotomic field $K=mathbb{Q}(e^{2pi i/n})$. Suppose that there exists some integer $m$ such that $f_n(m)=0 pmod {n^2}$, and there are primes $p$ and $q$ such that $p=f_n(z)$ and $q=f_n(z+a)$. Then $left(dfrac{a}{p}right)_n = left(dfrac{a}{q}right)_n$. When $n=3$, this conjecture agrees with cubic reciprocity theorems. The same is true for $n=4$.



Here is an example of the conjecture for $n=5$:



$f_5(x)=x^4+5x^3+10x^2+25$ and $f_5(0)=0pmod {5^2}$



$a=3$, $p=f_5(1)=41$ and $q=f_5(1+a)=f_5(4)=761$ are both prime, thus



$left(dfrac{3}{41}right)_5 = left(dfrac{3}{761}right)_5$.



Since $3$ is a quintic residue $pmod {41}$, then it is also a quintic residue of $761$. In general, if $p=f_5(3a+1)$ is prime, then $3$ is a quintic residue $pmod p$.










share|cite|improve this question















Let $left(dfrac{a}{p}right)_n$ be the $n$th power residue symbol such that when $a$ is an $n$th power residue $pmod p$, $left(dfrac{a}{p}right)_n=1$ otherwise $left(dfrac{a}{p}right)_n=zeta$. Let $f_n(x)$ be a defining polynomial for the $n$th cyclotomic field $K=mathbb{Q}(e^{2pi i/n})$. Suppose that there exists some integer $m$ such that $f_n(m)=0 pmod {n^2}$, and there are primes $p$ and $q$ such that $p=f_n(z)$ and $q=f_n(z+a)$. Then $left(dfrac{a}{p}right)_n = left(dfrac{a}{q}right)_n$. When $n=3$, this conjecture agrees with cubic reciprocity theorems. The same is true for $n=4$.



Here is an example of the conjecture for $n=5$:



$f_5(x)=x^4+5x^3+10x^2+25$ and $f_5(0)=0pmod {5^2}$



$a=3$, $p=f_5(1)=41$ and $q=f_5(1+a)=f_5(4)=761$ are both prime, thus



$left(dfrac{3}{41}right)_5 = left(dfrac{3}{761}right)_5$.



Since $3$ is a quintic residue $pmod {41}$, then it is also a quintic residue of $761$. In general, if $p=f_5(3a+1)$ is prime, then $3$ is a quintic residue $pmod p$.







elementary-number-theory cubic-reciprocity






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 21 at 7:29

























asked Nov 20 at 1:40









J. Linne

829315




829315








  • 2




    Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
    – KCd
    Nov 20 at 23:51












  • @KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
    – J. Linne
    Nov 21 at 7:32










  • For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
    – KCd
    Nov 21 at 11:24












  • @KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
    – J. Linne
    Nov 24 at 1:46
















  • 2




    Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
    – KCd
    Nov 20 at 23:51












  • @KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
    – J. Linne
    Nov 21 at 7:32










  • For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
    – KCd
    Nov 21 at 11:24












  • @KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
    – J. Linne
    Nov 24 at 1:46










2




2




Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
– KCd
Nov 20 at 23:51






Your $n$-th power residue symbol is not standard when $n > 2$: its value at numbers that are not $n$th powers mod $p$ should not be $-1$, but some $n$th root of unity if you want the symbol to be multiplicative in any reasonable way. Also, using ordinary prime numbers rather than prime ideals in $mathbf Z[e^{2pi i/n}]$ seems unusual, e.g., cubic reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/3}]$ and quartic (biquadratic) reciprocity is usually expressed in terms of $mathbf Z[e^{2pi i/4}] = mathbf Z[i]$. Your conjecture has a gap: what type of number is $z$?
– KCd
Nov 20 at 23:51














@KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
– J. Linne
Nov 21 at 7:32




@KCd changing -1 to a root of unity is only nessesary when dealing with cosets of the groups of $n$th power residues but I changed it anyways. As for $z$, like $x, a,$ and $n$ is an integer.
– J. Linne
Nov 21 at 7:32












For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
– KCd
Nov 21 at 11:24






For $n > 2$, an $n$th power residue symbol does not just have two nonzero values, "1 and $zeta$". Its nonzero values run over all $n$th roots of unity, in order to be multiplicative in $a$, so your description of $(frac{a}{p})_n$ is unusual (esp. since $p$ need not be prime in $mathbf Z[e^{2pi i/n}]$, e.g., $p = 41$ when $n = 5$. Where are you getting your description of power residue symbols from?
– KCd
Nov 21 at 11:24














@KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
– J. Linne
Nov 24 at 1:46






@KCd In theory, yes your assertion is correct, but here we only care about the solvability of $a=x^n pmod p$, and there is only two "values". Solvable $(1)$ or non-solvable $(-1)$ or a particular root of unity.
– J. Linne
Nov 24 at 1:46

















active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3005811%2fnth-power-residue-conjecture%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown






























active

oldest

votes













active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3005811%2fnth-power-residue-conjecture%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Le Mesnil-Réaume

Ida-Boy-Ed-Garten

web3.py web3.isConnected() returns false always