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13 votes
2 answers
664 views

Complexity of a weirdo two-dimensional sorting problem

Please forgive me if this is easy for some reason. Suppose given $S$, a set of $n^2$ points in $\mathbb{R}^2$. I want to choose a bijective map $f$ from $S$ to the set of lattice points in $\lbrace ...
JSE's user avatar
  • 19.2k
4 votes
1 answer
2k views

Under what conditions does an Integer Programming problem run in polynomial time?

Given $AX\leq B$ where $A\in\Bbb Z^{m\times n}$,$B\in\Bbb Z^m$ finding $X\in\Bbb Z^n$ where $m\geq n$ is the integer programming problem. If $A$ is totally unimodular then the problem is solvable in ...
Turbo's user avatar
  • 13.9k
4 votes
1 answer
204 views

Reference: Packing under translation is in NP

I am looking for a reference for a result that I am aware of. Let me describe the result. Given a polygon $C$ and polygons $p_1,\ldots,p_n$, it can be decided in NP time, if $p_1,\ldots,p_n$ can be ...
Till's user avatar
  • 479
3 votes
0 answers
105 views

Are there scenarios under which feasibility bilinear programming is easy?

Given $c\in\Bbb R^{n_1},d\in\Bbb R^{n_2}$, $E\in\Bbb R^{n_1\times n_2}$, $A\in\Bbb R^{m_1\times n_1}$, $B\in\Bbb R^{m_2\times n_2}$ $a\in\Bbb R^{m_1}$, $b\in\Bbb R^{m_2}$ and $t\in\Bbb R$ we know ...
Turbo's user avatar
  • 13.9k
2 votes
1 answer
240 views

Is the problem of vertex enumeration from an H-representation of a polytope NP-hard?

According to the Wikipedia page on the issue, the vertex enumeration problem is NP-hard. However, double description and reverse linear search are algorithms listed to solve the problem. Moreover, ...
Makogan's user avatar
  • 123
1 vote
1 answer
206 views

Show $0-1$ Knapsack is polynomially reducible to this problem

I have already posted this question here but have not received an answer so I am cross-posting with hope to reach a larger amount of mathematicians: Let $T=\{1,\cdots,n\}$ and consider the ...
Kuifje's user avatar
  • 225
1 vote
0 answers
1k views

How to solve simple bilinear equations under extra linear constraints

Hello, This is the full version of a question I asked earlier. I am trying to understand whether finding a solution to the following bilinear system is computationally hard or easy: $\lambda_i^T u_{...
Woland's user avatar
  • 53
0 votes
0 answers
171 views

Solve NP-hard type problems with linear programming

I would like to know if there is any way to solve an NP-hard type problem, for example, the TSP, sum of subsets or knapsack problem, by using linear programming and not by brute force. I ask this ...
Juan Carlos's user avatar