Classifying homomorphisms on polynomial rings with real coefficients.












2














Show that every homomorphism $mathbb{R}$[X] $rightarrow$ $mathbb{R}$[X] can is equal to $φ_g$ for a unique g $in$ $mathbb{R}$[X], given by $φ_g(f)$ = $f(g(X))$



My guess for any homomorphism $h$, $g = h(X)$ but I'm not sure how to proceed from there.










share|cite|improve this question






















  • Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
    – José Carlos Santos
    Nov 30 at 8:40






  • 1




    Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
    – Gnampfissimo
    Nov 30 at 9:00










  • Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
    – lhf
    Nov 30 at 10:07


















2














Show that every homomorphism $mathbb{R}$[X] $rightarrow$ $mathbb{R}$[X] can is equal to $φ_g$ for a unique g $in$ $mathbb{R}$[X], given by $φ_g(f)$ = $f(g(X))$



My guess for any homomorphism $h$, $g = h(X)$ but I'm not sure how to proceed from there.










share|cite|improve this question






















  • Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
    – José Carlos Santos
    Nov 30 at 8:40






  • 1




    Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
    – Gnampfissimo
    Nov 30 at 9:00










  • Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
    – lhf
    Nov 30 at 10:07
















2












2








2







Show that every homomorphism $mathbb{R}$[X] $rightarrow$ $mathbb{R}$[X] can is equal to $φ_g$ for a unique g $in$ $mathbb{R}$[X], given by $φ_g(f)$ = $f(g(X))$



My guess for any homomorphism $h$, $g = h(X)$ but I'm not sure how to proceed from there.










share|cite|improve this question













Show that every homomorphism $mathbb{R}$[X] $rightarrow$ $mathbb{R}$[X] can is equal to $φ_g$ for a unique g $in$ $mathbb{R}$[X], given by $φ_g(f)$ = $f(g(X))$



My guess for any homomorphism $h$, $g = h(X)$ but I'm not sure how to proceed from there.







abstract-algebra ring-homomorphism polynomial-rings






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 30 at 8:40







user621286



















  • Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
    – José Carlos Santos
    Nov 30 at 8:40






  • 1




    Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
    – Gnampfissimo
    Nov 30 at 9:00










  • Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
    – lhf
    Nov 30 at 10:07




















  • Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
    – José Carlos Santos
    Nov 30 at 8:40






  • 1




    Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
    – Gnampfissimo
    Nov 30 at 9:00










  • Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
    – lhf
    Nov 30 at 10:07


















Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
– José Carlos Santos
Nov 30 at 8:40




Welcome to MSE. Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please edit the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
– José Carlos Santos
Nov 30 at 8:40




1




1




Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
– Gnampfissimo
Nov 30 at 9:00




Your guess is right! Now you can directly calculate $h(f) = varphi_g(f)$ for any $f$ explicitly, using that $h$ is a homomorphism.
– Gnampfissimo
Nov 30 at 9:00












Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
– lhf
Nov 30 at 10:07






Every homomorphism of $mathbb R$-algebras, that is, fixing $mathbb R$.
– lhf
Nov 30 at 10:07

















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',
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%2f3019835%2fclassifying-homomorphisms-on-polynomial-rings-with-real-coefficients%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%2f3019835%2fclassifying-homomorphisms-on-polynomial-rings-with-real-coefficients%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

Sphinx de Gizeh

Dijon

Équipe cycliste