From 808cb694905a896c45ba3bc3d744ae5b4e2efe3c Mon Sep 17 00:00:00 2001 From: Yu Cong Date: Sat, 25 Apr 2026 13:46:32 +0800 Subject: [PATCH] zzz --- notes.tex | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/notes.tex b/notes.tex index 8e52141..81be628 100644 --- a/notes.tex +++ b/notes.tex @@ -5,7 +5,6 @@ \geometry{margin=2cm} \title{A Note on Interdiction of Linear Minimization Problems} -\author{Yu Cong \and Kangyi Tian} \date{\today} \DeclareMathOperator*{\opt}{OPT} @@ -40,26 +39,13 @@ The linear minimization interdiction problem considered here is \begin{equation}\label{eq:interdiction} \opt = - \min_{\substack{S\in\mathcal F,\; R\subseteq S\\ c(R)\leq b}} - w(S\setminus R), + \min \set{w(S\setminus R)\;|\;S\in\mathcal F,\; R\subseteq S,c(R)\leq b}, \end{equation} where $c(R)=\sum_{e\in R}c(e)$. This is equivalent to first deleting an arbitrary set $R$ with $c(R)\leq b$ and then minimizing $w(S\setminus R)$ over $S\in\mathcal F$, because only $R\cap S$ affects the value of a chosen feasible set $S$. -Connectivity interdiction is the special case where $\mathcal F$ is the family -of cuts of a graph. In that case \eqref{eq:interdiction} is exactly the -$b$-free min-cut formulation -\[ - \min_{\substack{\text{cut } C,\;R\subseteq C\\c(R)\leq b}} - w(C\setminus R). -\] - -The argument below uses both minimization and linearity. Minimization gives the -near-minimizer certificate in \autoref{thm:two-approx-witness}; linearity gives -the truncation formula $w_\lambda(e)=\min\{w(e),\lambda c(e)\}$. - \section{Lagrangian relaxation} It is helpful to first look at \eqref{eq:interdiction} as an integer program,