What can be the convex relaxation of a quadratic matrix inequality?












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I am trying to relax the Quadratic Matrix Inequality given as:
$$W leq X^TX+Y^TY \ Wgeq 0 $$ Here, $X,Y,W in mathbb{R}^{ntimes n}$ matrices. These two are to be solved along with one linear matrix inequality in $W, X,$ and $Y$.



My attempt:
I tried applying the Schur Complement lemma as:
$$begin{bmatrix} X^TX-W& Y^T\ Y & I end{bmatrix}geq 0$$
But this is making the problem infeasible as I understand that there is no solution such that $X^TXgeq W$ along with other constraints.



how can I relax this Quadratic Matrix Inequality?










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  • $begingroup$
    the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
    $endgroup$
    – LinAlg
    Dec 6 '18 at 21:47


















0












$begingroup$


I am trying to relax the Quadratic Matrix Inequality given as:
$$W leq X^TX+Y^TY \ Wgeq 0 $$ Here, $X,Y,W in mathbb{R}^{ntimes n}$ matrices. These two are to be solved along with one linear matrix inequality in $W, X,$ and $Y$.



My attempt:
I tried applying the Schur Complement lemma as:
$$begin{bmatrix} X^TX-W& Y^T\ Y & I end{bmatrix}geq 0$$
But this is making the problem infeasible as I understand that there is no solution such that $X^TXgeq W$ along with other constraints.



how can I relax this Quadratic Matrix Inequality?










share|cite|improve this question









$endgroup$












  • $begingroup$
    the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
    $endgroup$
    – LinAlg
    Dec 6 '18 at 21:47
















0












0








0





$begingroup$


I am trying to relax the Quadratic Matrix Inequality given as:
$$W leq X^TX+Y^TY \ Wgeq 0 $$ Here, $X,Y,W in mathbb{R}^{ntimes n}$ matrices. These two are to be solved along with one linear matrix inequality in $W, X,$ and $Y$.



My attempt:
I tried applying the Schur Complement lemma as:
$$begin{bmatrix} X^TX-W& Y^T\ Y & I end{bmatrix}geq 0$$
But this is making the problem infeasible as I understand that there is no solution such that $X^TXgeq W$ along with other constraints.



how can I relax this Quadratic Matrix Inequality?










share|cite|improve this question









$endgroup$




I am trying to relax the Quadratic Matrix Inequality given as:
$$W leq X^TX+Y^TY \ Wgeq 0 $$ Here, $X,Y,W in mathbb{R}^{ntimes n}$ matrices. These two are to be solved along with one linear matrix inequality in $W, X,$ and $Y$.



My attempt:
I tried applying the Schur Complement lemma as:
$$begin{bmatrix} X^TX-W& Y^T\ Y & I end{bmatrix}geq 0$$
But this is making the problem infeasible as I understand that there is no solution such that $X^TXgeq W$ along with other constraints.



how can I relax this Quadratic Matrix Inequality?







convex-optimization nonlinear-optimization semidefinite-programming relaxations






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share|cite|improve this question











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asked Dec 6 '18 at 7:47









Parikshit PareekParikshit Pareek

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  • $begingroup$
    the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
    $endgroup$
    – LinAlg
    Dec 6 '18 at 21:47




















  • $begingroup$
    the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
    $endgroup$
    – LinAlg
    Dec 6 '18 at 21:47


















$begingroup$
the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
$endgroup$
– LinAlg
Dec 6 '18 at 21:47






$begingroup$
the squared term is on the wrong side of the inequality for the Schur complement; perhaps you can substitute $Z=X^TX$, $Zsucceq 0$.
$endgroup$
– LinAlg
Dec 6 '18 at 21:47












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