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











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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?










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  • 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















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