Revisit “Inequality between Frobenius and nuclear norm”
$begingroup$
I am reading the following question:
Inequality between Frobenius and nuclear norm
I know $$|X|_* = sum_{i=1}^r sigma_i(X)$$and $$|X|_F = bigg(sum_{i=1}^r sigma^2_i(X)bigg)^{1/2}$$
I try to prove it by Cauchy-Schwarz inequality; however, I cannot see how to use C-S inequality to prove this. Could anyone please give me a small hint? Thanks in advanced.
linear-algebra matrices cauchy-schwarz-inequality nuclear-norm
$endgroup$
add a comment |
$begingroup$
I am reading the following question:
Inequality between Frobenius and nuclear norm
I know $$|X|_* = sum_{i=1}^r sigma_i(X)$$and $$|X|_F = bigg(sum_{i=1}^r sigma^2_i(X)bigg)^{1/2}$$
I try to prove it by Cauchy-Schwarz inequality; however, I cannot see how to use C-S inequality to prove this. Could anyone please give me a small hint? Thanks in advanced.
linear-algebra matrices cauchy-schwarz-inequality nuclear-norm
$endgroup$
add a comment |
$begingroup$
I am reading the following question:
Inequality between Frobenius and nuclear norm
I know $$|X|_* = sum_{i=1}^r sigma_i(X)$$and $$|X|_F = bigg(sum_{i=1}^r sigma^2_i(X)bigg)^{1/2}$$
I try to prove it by Cauchy-Schwarz inequality; however, I cannot see how to use C-S inequality to prove this. Could anyone please give me a small hint? Thanks in advanced.
linear-algebra matrices cauchy-schwarz-inequality nuclear-norm
$endgroup$
I am reading the following question:
Inequality between Frobenius and nuclear norm
I know $$|X|_* = sum_{i=1}^r sigma_i(X)$$and $$|X|_F = bigg(sum_{i=1}^r sigma^2_i(X)bigg)^{1/2}$$
I try to prove it by Cauchy-Schwarz inequality; however, I cannot see how to use C-S inequality to prove this. Could anyone please give me a small hint? Thanks in advanced.
linear-algebra matrices cauchy-schwarz-inequality nuclear-norm
linear-algebra matrices cauchy-schwarz-inequality nuclear-norm
asked Dec 5 '18 at 22:25
DennyDenny
31729
31729
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Cauchy—Schwarz tells you that
$$
sum_{i=1}^r a_i b_i leq left(sum_{i=1}^r a_i^2right)^{1/2}left(sum_{i=1}^r b_i^2right)^{1/2}
$$
Apply it with $a_i = 1$, $b_i = sigma_i(X)$ (for $1leq ileq r$).
$endgroup$
add a comment |
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
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3027733%2frevisit-inequality-between-frobenius-and-nuclear-norm%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
$begingroup$
Cauchy—Schwarz tells you that
$$
sum_{i=1}^r a_i b_i leq left(sum_{i=1}^r a_i^2right)^{1/2}left(sum_{i=1}^r b_i^2right)^{1/2}
$$
Apply it with $a_i = 1$, $b_i = sigma_i(X)$ (for $1leq ileq r$).
$endgroup$
add a comment |
$begingroup$
Cauchy—Schwarz tells you that
$$
sum_{i=1}^r a_i b_i leq left(sum_{i=1}^r a_i^2right)^{1/2}left(sum_{i=1}^r b_i^2right)^{1/2}
$$
Apply it with $a_i = 1$, $b_i = sigma_i(X)$ (for $1leq ileq r$).
$endgroup$
add a comment |
$begingroup$
Cauchy—Schwarz tells you that
$$
sum_{i=1}^r a_i b_i leq left(sum_{i=1}^r a_i^2right)^{1/2}left(sum_{i=1}^r b_i^2right)^{1/2}
$$
Apply it with $a_i = 1$, $b_i = sigma_i(X)$ (for $1leq ileq r$).
$endgroup$
Cauchy—Schwarz tells you that
$$
sum_{i=1}^r a_i b_i leq left(sum_{i=1}^r a_i^2right)^{1/2}left(sum_{i=1}^r b_i^2right)^{1/2}
$$
Apply it with $a_i = 1$, $b_i = sigma_i(X)$ (for $1leq ileq r$).
answered Dec 5 '18 at 22:38
Clement C.Clement C.
49.8k33886
49.8k33886
add a comment |
add a comment |
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.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3027733%2frevisit-inequality-between-frobenius-and-nuclear-norm%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
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