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9 votes
1 answer
295 views

Definition of packing property

Definition 1: A clutter $C$ is said to have the packing property if $C$ and all of its minors satisfy the König property. where, vertex cover of $C$ is a set of vertices that have non-empty ...
user177523's user avatar
10 votes
0 answers
722 views

Fractional Matching version of Hall's Marriage theorem

Let $G=(S,T,E)$ be a bipartite graph, $|S|=|T|$. Then the following are equivalent: 1) there exist a perfect matching in $G$; 2) there exist non-negative weights on edges such that the sum of ...
Fedor Petrov's user avatar
2 votes
0 answers
177 views

Formulating shortest path as submodular minimization

I'm curious about the general question of whether any combinatorial optimization problem with polynomial time solution can necessarily be reformulated as minimizing a submodular function. The answer ...
user306101's user avatar
1 vote
1 answer
219 views

approximate diameter of polytopes in high dimensions

I just came across the following problem: Let us consider the unit corner of the n-cube $$ \Delta^n = \left\{(t_1,\cdots,t_n)\in\mathbb{R}^n\mid\sum_{i = 1}^{n}{t_i} \leq 1 \mbox{ and } t_i \ge 0 \...
rjm's user avatar
  • 75
2 votes
1 answer
426 views

Network flows with shared capacities

Suppose we have a flow network, with capacity constraints on weighted sums of arc flows, such as: $$2 f(1, 2) + 3 f(4, 5) + f(3, 7) \leq 10,$$ where $f(1, 2)$ denotes the flow through arc $(1, 2)$....
robertdg's user avatar
5 votes
0 answers
194 views

A linear optimization problem on a graph

Let $G=(V,E)$ be a finite graph and let $f$ be any positive function defined on the vertices. Put weights on the vertices $v_{i}$, way $w_{i}$ so that $\sum_{i=1}^{n}w_{i}\leq 1$. Assume that every ...
TOM's user avatar
  • 2,288