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world:kkt

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world:kkt [2025/10/08 02:09]
rdouc [Weak duality]
world:kkt [2025/10/08 02:30] (current)
rdouc
Line 135: Line 135:
 <hidden Click here to see the proof> <hidden Click here to see the proof>
 $\bproof$ $\bproof$
-Assume now that $f(x^*)=\inf_{x\in \mcD} f(x)$ for some $x^* \in\mcD$. Then, $\{f-f(x^*)<​0\} \cap \mcD =\emptyset$ so that there exists $\lambda^* \geq 0$ satisfying for all $x\in \mcD$, $f(x)-f(x^*)+\sum_{i=1}^n \lambda^*_i h_i(x) \geq 0$. And this implies that $(x^*,​\lambda^*)$ is a saddle point since: for all $\lambda \geq 0$ and $x \in \Xset$, ​+Assume now that $f(x^*)=\inf_{x\in \mcD} f(x)$ for some $x^* \in\mcD$. Then, $\{f-f(x^*)<​0\} \cap \mcD =\emptyset$ so that there exists $\lambda^* \geq 0$ satisfying for all $x\in \Xset$, $f(x)-f(x^*)+\sum_{i=1}^n \lambda^*_i h_i(x) \geq 0$. And this implies that $(x^*,​\lambda^*)$ is a saddle point since: for all $\lambda \geq 0$ and $x \in \Xset$, ​
 $$ $$
 f(x^*)+\sum_{i=1}^n \lambda_i h_i(x^*) \leq f(x^*) \leq f(x)+\sum_{i=1}^n \lambda^*_i h_i(x) ​ f(x^*)+\sum_{i=1}^n \lambda_i h_i(x^*) \leq f(x^*) \leq f(x)+\sum_{i=1}^n \lambda^*_i h_i(x) ​
world/kkt.1759882195.txt.gz · Last modified: 2025/10/08 02:09 by rdouc