Proximity Theorem and FPT Algorithm for Minimum Group-labeled Matroid Bases

Let \(M\) be a matroid, let \(\ell:E(M)\to G\) be a labeling of its elements by an abelian group, and let \(F\subseteq G\) be finite. A base is \emph{\(F\)-avoiding} if the label sum of its elements is not in $F$. We prove that, for arbitrary costs, a min-cost \(F\)-avoiding base can be obtained from any min-cost … Read more

A Short Proof of Tight Bounds on the Smallest Support Size of Integer Solutions to Linear Equations

In this note, we study the size of the support of solutions to linear Diophantine equations $Ax=b, ~x\in\Z^n$ where $A\in\Z^{m\times n}, b\in\Z^n$. We give an asymptotically tight upper bound on the smallest support size, parameterized by $\|A\|_\infty$ and $m$, and taken as a worst case over all $b$ such that the above system has a … Read more