Let $Z_i(G)$ be the terms of the upper central series of $G$. Let $H trianglelefteq G$. Show $Z_i(G)H/H...












1












$begingroup$


Let $Z_0(G) = { 1 }$ and:



$$Z_{i + 1}(G)/Z_i(G) = Z(G/Z_i(G))$$



(as defined in dummit and foote).
I want to show that $Z_i(G)H/H subseteq Z_i(G/H)$.
I can see it's true for $i = 0$ and $i = 1$, but I'm stuck in the inductive case because I have to work with quotients of quotients (and not in the form $(G/H)/(K/H)$ so no 3rd isomorphism theorem).



In other words, I have an element $zH in Z_{i + 1}(G)H/H$.
I want to show that it is in $Z_{i + 1}(G/H)$, which is defined recursively as



$$Z_{i + 1}(G/H)/Z_i(G/H) = Z((G/H)/Z_i(G/H)).$$










share|cite|improve this question











$endgroup$












  • $begingroup$
    Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
    $endgroup$
    – darij grinberg
    Dec 7 '18 at 2:44
















1












$begingroup$


Let $Z_0(G) = { 1 }$ and:



$$Z_{i + 1}(G)/Z_i(G) = Z(G/Z_i(G))$$



(as defined in dummit and foote).
I want to show that $Z_i(G)H/H subseteq Z_i(G/H)$.
I can see it's true for $i = 0$ and $i = 1$, but I'm stuck in the inductive case because I have to work with quotients of quotients (and not in the form $(G/H)/(K/H)$ so no 3rd isomorphism theorem).



In other words, I have an element $zH in Z_{i + 1}(G)H/H$.
I want to show that it is in $Z_{i + 1}(G/H)$, which is defined recursively as



$$Z_{i + 1}(G/H)/Z_i(G/H) = Z((G/H)/Z_i(G/H)).$$










share|cite|improve this question











$endgroup$












  • $begingroup$
    Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
    $endgroup$
    – darij grinberg
    Dec 7 '18 at 2:44














1












1








1





$begingroup$


Let $Z_0(G) = { 1 }$ and:



$$Z_{i + 1}(G)/Z_i(G) = Z(G/Z_i(G))$$



(as defined in dummit and foote).
I want to show that $Z_i(G)H/H subseteq Z_i(G/H)$.
I can see it's true for $i = 0$ and $i = 1$, but I'm stuck in the inductive case because I have to work with quotients of quotients (and not in the form $(G/H)/(K/H)$ so no 3rd isomorphism theorem).



In other words, I have an element $zH in Z_{i + 1}(G)H/H$.
I want to show that it is in $Z_{i + 1}(G/H)$, which is defined recursively as



$$Z_{i + 1}(G/H)/Z_i(G/H) = Z((G/H)/Z_i(G/H)).$$










share|cite|improve this question











$endgroup$




Let $Z_0(G) = { 1 }$ and:



$$Z_{i + 1}(G)/Z_i(G) = Z(G/Z_i(G))$$



(as defined in dummit and foote).
I want to show that $Z_i(G)H/H subseteq Z_i(G/H)$.
I can see it's true for $i = 0$ and $i = 1$, but I'm stuck in the inductive case because I have to work with quotients of quotients (and not in the form $(G/H)/(K/H)$ so no 3rd isomorphism theorem).



In other words, I have an element $zH in Z_{i + 1}(G)H/H$.
I want to show that it is in $Z_{i + 1}(G/H)$, which is defined recursively as



$$Z_{i + 1}(G/H)/Z_i(G/H) = Z((G/H)/Z_i(G/H)).$$







group-theory nilpotent-groups






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 7 '18 at 2:27









darij grinberg

10.5k33062




10.5k33062










asked Dec 7 '18 at 2:25









RaekyeRaekye

24539




24539












  • $begingroup$
    Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
    $endgroup$
    – darij grinberg
    Dec 7 '18 at 2:44


















  • $begingroup$
    Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
    $endgroup$
    – darij grinberg
    Dec 7 '18 at 2:44
















$begingroup$
Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
$endgroup$
– darij grinberg
Dec 7 '18 at 2:44




$begingroup$
Rewrite the recursive definition as $Z_{i+1}left(Gright) = left{g in G mid ghg^{-1}h^{-1} in Z_ileft(Gright) text{ for all } h in G right}$. Do you now see why each $Z_i$ is functorial wrt surjective homomorphisms (i.e., each surjective group homomorphism $f : G to H$ sends $Z_ileft(Gright)$ into $Z_ileft(Hright)$ for each $i$)?
$endgroup$
– darij grinberg
Dec 7 '18 at 2:44










0






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%2f3029387%2flet-z-ig-be-the-terms-of-the-upper-central-series-of-g-let-h-trianglele%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






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.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3029387%2flet-z-ig-be-the-terms-of-the-upper-central-series-of-g-let-h-trianglele%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

Ellipse (mathématiques)

Quarter-circle Tiles

Mont Emei