Number theory: Unit group of ring of integer of number field












1












$begingroup$


Somebody can help me proof the unit group of ring of integer of 5th cyclotomic field is infinite










share|cite|improve this question











$endgroup$












  • $begingroup$
    What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
    $endgroup$
    – reuns
    Jan 16 at 11:16


















1












$begingroup$


Somebody can help me proof the unit group of ring of integer of 5th cyclotomic field is infinite










share|cite|improve this question











$endgroup$












  • $begingroup$
    What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
    $endgroup$
    – reuns
    Jan 16 at 11:16
















1












1








1





$begingroup$


Somebody can help me proof the unit group of ring of integer of 5th cyclotomic field is infinite










share|cite|improve this question











$endgroup$




Somebody can help me proof the unit group of ring of integer of 5th cyclotomic field is infinite







abstract-algebra number-theory






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 16 at 9:04









Bernard

121k740116




121k740116










asked Jan 16 at 7:36









LeHoaiNamLeHoaiNam

62




62












  • $begingroup$
    What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
    $endgroup$
    – reuns
    Jan 16 at 11:16




















  • $begingroup$
    What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
    $endgroup$
    – reuns
    Jan 16 at 11:16


















$begingroup$
What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
$endgroup$
– reuns
Jan 16 at 11:16






$begingroup$
What is the inverse of $a+b sqrt{5} in mathbb{Z}[ sqrt{5}]$, when is it a unit en.wikipedia.org/wiki/Pell%27s_equation
$endgroup$
– reuns
Jan 16 at 11:16












1 Answer
1






active

oldest

votes


















2












$begingroup$

Can you prove that $Bbb Q(zeta_5)$ contains $Bbb Q(sqrt5)$?



And can you prove that the integer ring of $Bbb Q(sqrt5)$ has infinitely
many units?






share|cite|improve this answer









$endgroup$













  • $begingroup$
    I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
    $endgroup$
    – LeHoaiNam
    Jan 16 at 8:06











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',
autoActivateHeartbeat: false,
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%2f3075427%2fnumber-theory-unit-group-of-ring-of-integer-of-number-field%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









2












$begingroup$

Can you prove that $Bbb Q(zeta_5)$ contains $Bbb Q(sqrt5)$?



And can you prove that the integer ring of $Bbb Q(sqrt5)$ has infinitely
many units?






share|cite|improve this answer









$endgroup$













  • $begingroup$
    I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
    $endgroup$
    – LeHoaiNam
    Jan 16 at 8:06
















2












$begingroup$

Can you prove that $Bbb Q(zeta_5)$ contains $Bbb Q(sqrt5)$?



And can you prove that the integer ring of $Bbb Q(sqrt5)$ has infinitely
many units?






share|cite|improve this answer









$endgroup$













  • $begingroup$
    I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
    $endgroup$
    – LeHoaiNam
    Jan 16 at 8:06














2












2








2





$begingroup$

Can you prove that $Bbb Q(zeta_5)$ contains $Bbb Q(sqrt5)$?



And can you prove that the integer ring of $Bbb Q(sqrt5)$ has infinitely
many units?






share|cite|improve this answer









$endgroup$



Can you prove that $Bbb Q(zeta_5)$ contains $Bbb Q(sqrt5)$?



And can you prove that the integer ring of $Bbb Q(sqrt5)$ has infinitely
many units?







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 16 at 7:47









Lord Shark the UnknownLord Shark the Unknown

105k1160132




105k1160132












  • $begingroup$
    I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
    $endgroup$
    – LeHoaiNam
    Jan 16 at 8:06


















  • $begingroup$
    I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
    $endgroup$
    – LeHoaiNam
    Jan 16 at 8:06
















$begingroup$
I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
$endgroup$
– LeHoaiNam
Jan 16 at 8:06




$begingroup$
I'm not sure. I'm reading " Number theory and fermat's last theory" (Ivan Stewart) and doing exercise 5 subsection 3.3 page 72. I can't solve it by the way that author gave! Can you show me more detail, sir!
$endgroup$
– LeHoaiNam
Jan 16 at 8:06


















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.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3075427%2fnumber-theory-unit-group-of-ring-of-integer-of-number-field%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

MongoDB - Not Authorized To Execute Command

in spring boot 2.1 many test slices are not allowed anymore due to multiple @BootstrapWith

How to fix TextFormField cause rebuild widget in Flutter