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1 vote
1 answer
186 views

Practical/heuristic algorithm for multi set-cover

Consider a universe $N$ containing $n$ elements, and a collection of sets $\mathcal{C}$, over $N$. The $k$-multiset multicover (MSMC) problem is to cover all elements of the universe $N$ at least $k$ ...
Vivek Bagaria's user avatar
6 votes
2 answers
396 views

Finding smallest context free grammar that generates a set of sets

Are there any results known about the size of smallest context free grammar that generates a set of sets? That is, I am given an alphabet $\Sigma$ as well as a set $S \subseteq \mathbb{P}(\Sigma)$ ...
Shahab's user avatar
  • 338
3 votes
0 answers
142 views

Complexity of minimizing monotone arithmetical formulas

Let's say that I have a multi-variate arithmetical expression $A(x_1, \ldots, x_n)$ that uses addition and multiplication operations and is also in a very simple form of sums of products, e.g., $A_1(...
Shahab's user avatar
  • 338
1 vote
1 answer
108 views

Approximations for the Stable Fixtures Problem

I have a set of N items, each with a subset of those items they can be paired with; each pair has a weight. I'd like to choose pairs to maximize the total weight, subject to each item being in at ...
Doctor J's user avatar
  • 113
4 votes
0 answers
160 views

Find index set partition that has large projections

I have a multiset $S$ of $n$-bit strings. Let $1_S(s)$ denote the number of times that string $s$ appears in $S$, i.e., the multiplicity of $s$ in $S$. I want to find a partition of $\{1,2,\dots,n\}$...
D.W.'s user avatar
  • 12.4k
8 votes
3 answers
402 views

Find the nearest $d+1$ corners of a cube in $\mathbb{R}^d$

How can one find the $d+1$ corners of the unit cube in $\mathbb{R}^d$ nearest a point $x$ in the cube ? Use the L1 metric, so that in 4d |$x$ - 0000| = $\sum {x_i}$, |$x$ - 0001| = $x_3 + x_2 + x_1 + ...
Denis's user avatar
  • 323
7 votes
1 answer
510 views

Does this bin packing problem have a name?

My problem is related to the standard bin packing problem (where you have bins of capacity $1$, items of capacity $(0,1]$, and want to pack the items into as few bins as possible), but there are a ...
Magnus Lie Hetland's user avatar
5 votes
1 answer
168 views

Local Smoothness vs optimisation in combinatorial problems

Local smoothness is often mentioned in literature analysing different heuristics and meta-heuristics for combinatorial optimisation. What is meant precisely by local smoothness is often left out, but ...
zenna's user avatar
  • 835