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@ -167,8 +167,9 @@
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}
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% more theorem env
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\newtheorem{observation}{Observation}
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\newtheorem{question}{Question}
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\newtheorem{conjecture}[theorem]{Conjecture}
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\newtheorem{observation}[theorem]{Observation}
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\newtheorem{question}[theorem]{Question}
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% ----------------------------------------------------------------------
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main.tex
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main.tex
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\documentclass{beamer}
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\usepackage{nicefrac}
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\DeclareMathOperator*{\opt}{OPT}
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\title[Edge Conn Interdiction]{Faster FPTAS for Edge Connectivity Interdiction}
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\date{\today}
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@ -78,7 +79,7 @@ The input is a graph $G=(V,E)$ with edge weights $w:E\to \Z_+$ and edge removal
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Let $\tau$ be the optimum of Normalized Mincut. Consider a truncated weight $w_\tau(e)= \min \{w(e),c(e)\tau\}$.
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\begin{theorem}
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\begin{theorem}\label{thm:2approx}
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The optimal cut $C^*$ for Connectivity Interdiction is a 2-approximation of global mincut with weights $w_\tau$.
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\end{theorem}
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\end{frame}
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@ -168,7 +169,21 @@ s.t.& & \sum_{T\ni e} z_T &\leq w(e) & &\forall e\in E\\
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Again we first assume the $\mu$ is fixed. Then for each pair of constraints $\sum z_T \leq w(e)$ and $\sum z_T \leq c(e)\mu$ only one of them works. The real capacity for this fractional tree packing is $\min\{w(e),c(e)\mu\}$, which is exactly the truncated weight $w_\tau$.
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\end{frame}
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\begin{frame}{Integrality Gap}
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\begin{conjecture}
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ILP\ref{IP} has an integrality gap of 4.
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\end{conjecture}
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Suppose $\mu^*$ is the optimal solution to LP\ref{lp:dualcutint}. Let $\lambda^{fr}$ be the fractional mincut with capacity $w_\mu$.
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we have
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\begin{align*}
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4\opt(LP) &=4\lambda^{fr}-4b\mu^*\\
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&\geq 2\lambda^{int} - 4b\mu^*\\
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&\geq w_{\mu^*}(C^*)-b\mu^*,
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\end{align*}
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which implies Theorem \autoref{thm:2approx}.
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\end{frame}
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\begin{frame}{References}
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\bibliographystyle{plainnat}
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\bibliography{ref}
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