Why is strong duality holds even though the problem is not convex?











up vote
0
down vote

favorite












I write the question $5.29$ in Convex Optimization ,and it said



minimize $-3x_1^2+x_2^2+2x_3^2+2(x_1+x_2+x_3)$



subject to $x_1^2+x_2^2+x_3^2=1$



so strong duality holds even though the problem is not convex



I wonder that if we have to prove it is strong duality and not convex,how should we prove it?










share|cite|improve this question






















  • Perhaps you can read page 229 of the book (which is referred to from the question).
    – LinAlg
    Nov 26 at 14:28










  • The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
    – A.Γ.
    Dec 7 at 21:56















up vote
0
down vote

favorite












I write the question $5.29$ in Convex Optimization ,and it said



minimize $-3x_1^2+x_2^2+2x_3^2+2(x_1+x_2+x_3)$



subject to $x_1^2+x_2^2+x_3^2=1$



so strong duality holds even though the problem is not convex



I wonder that if we have to prove it is strong duality and not convex,how should we prove it?










share|cite|improve this question






















  • Perhaps you can read page 229 of the book (which is referred to from the question).
    – LinAlg
    Nov 26 at 14:28










  • The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
    – A.Γ.
    Dec 7 at 21:56













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I write the question $5.29$ in Convex Optimization ,and it said



minimize $-3x_1^2+x_2^2+2x_3^2+2(x_1+x_2+x_3)$



subject to $x_1^2+x_2^2+x_3^2=1$



so strong duality holds even though the problem is not convex



I wonder that if we have to prove it is strong duality and not convex,how should we prove it?










share|cite|improve this question













I write the question $5.29$ in Convex Optimization ,and it said



minimize $-3x_1^2+x_2^2+2x_3^2+2(x_1+x_2+x_3)$



subject to $x_1^2+x_2^2+x_3^2=1$



so strong duality holds even though the problem is not convex



I wonder that if we have to prove it is strong duality and not convex,how should we prove it?







convex-analysis convex-optimization duality-theorems






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 26 at 13:09









shineele

377




377












  • Perhaps you can read page 229 of the book (which is referred to from the question).
    – LinAlg
    Nov 26 at 14:28










  • The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
    – A.Γ.
    Dec 7 at 21:56


















  • Perhaps you can read page 229 of the book (which is referred to from the question).
    – LinAlg
    Nov 26 at 14:28










  • The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
    – A.Γ.
    Dec 7 at 21:56
















Perhaps you can read page 229 of the book (which is referred to from the question).
– LinAlg
Nov 26 at 14:28




Perhaps you can read page 229 of the book (which is referred to from the question).
– LinAlg
Nov 26 at 14:28












The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
– A.Γ.
Dec 7 at 21:56




The problem actually becomes convex if we substitute $x_1^2=1-x_2^2-x_3^2$ and $x_1=-sqrt{1-x_2^2-x_3^2}$ into the objective function subject to $x_2^2+x_3^2le 1$.
– A.Γ.
Dec 7 at 21:56















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%2f3014311%2fwhy-is-strong-duality-holds-even-though-the-problem-is-not-convex%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%2f3014311%2fwhy-is-strong-duality-holds-even-though-the-problem-is-not-convex%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

Wiesbaden

Marschland

Dieringhausen