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1
vote
1answer
90 views

Easier and Harder instances of NP-complete problems?

Following previous questions here and here around $NP$-complete problems (and P vs NP). Are there "easier" or "harder" (sets of) instances of an $NP$-complete problem? If yes (which i assume), how a ...
0
votes
1answer
94 views

Any result connecting an NP-complete problem with slight super-polynomial time?

Helo everybody, is there any result or research that connects some $NP$-complete problem with only slightly super-polynomial (strongly sub-exponential) time? This would not necessarily ...
9
votes
0answers
119 views

Complexity question from mathematical music theory

Fix an positive integer $N$. A row means any linear ordering $R=(n_i)_{0\leq i <N}$ of the additive group ${\Bbb Z}/N{\Bbb Z}$. Call $R$ a (generalized) all-interval row if the elements of the ...
6
votes
2answers
304 views

Proof for ACYCLIC PARTITION being NP-complete

I'm new to this site, so please pardon me for any mistakes and please feel free to edit the question to help get better answers. I'm interested in reading any proof of ACYCLIC PARTITION (Garey and ...
15
votes
1answer
250 views

Natural candidate against the Isomorphism Conjecture?

The famous Isomorphism Conjecture of Berman and Hartmanis says that all $NP$-complete languages are polynomial time isomorphic (p-isomorphic) to each other. The key significance of the conjecture is ...
7
votes
1answer
219 views

Can a natural graph problem be universally hard?

Is there a natural $\mathsf{NP}$-complete graph problem, which remains $\mathsf{NP}$-complete even when it is restricted to any polynomial-time recognizable graph class? To avoid degenerated cases, ...
2
votes
1answer
191 views

Multiple subset sum where subsets have complementary cardinality

$\underline{\mathsf{EQUAL\mbox{ }k-COMPLEMENTARY\mbox{ }SUBSET\mbox{ }SUM(EkCSS)} }$Problem: Input: $a_1,\dots,a_n,b\in \mathbb Z$, with distinct $a_i$ and $k\in\Bbb Z^+$. Output: $k$ $\mbox{ ...
3
votes
0answers
72 views

Symmetry of optimal solutions to discrete optimization problems

Given a graph, say one wants to find the clique number, independence number, chromatic number, vertex cover number etc., one knows that a solution exists. However if the solution space has more than ...
4
votes
1answer
151 views

Are there any implementations for zero-knowledge proofs of NP-complete problems?

It's been known for a long time that any claim in NP has a zero-knowledge proof for it. Has anybody actually implemented a zero-knowledge proof system for a NP-complete language? Using a search ...
0
votes
0answers
200 views

Are there upper bounds on the worst case complexity of NP-complete problems?

I have proven some problem to be (weakly) NP-complete and try to find out some algorithm to solve it exactly. Except for some pseudo-polynomial stuff, I would be happy with an algorithm running in ...
6
votes
0answers
118 views

Generalization of SAT, where we replace OR with another symmetric function

Let $\sigma(y_1,\dots,y_k)$ denote some boolean symmetric function on $k$ boolean inputs, $\sigma:\{0,1\}^k\to\{0,1\}$. In $k$-SAT, an instance is a conjunction of clauses, where each clause is the ...
2
votes
1answer
193 views

Complexity of a linear algebra problem

Let matrix $M \in \{0,1\}^{r \times s}$ ($s>r$), let function $f:\Bbb Z^{} \rightarrow \pm1$ and let $\alpha \in \Bbb Z \cap (0,s)$ be given. Is it NP-complete to decide if $\exists u \in ...
-2
votes
2answers
451 views

Where are NP-complete problems if P=NP [closed]

Where are exactly NP-complete problems if P=NP? They will be definitely in P, but will they be P-complete?
2
votes
2answers
159 views

Finding the identity with permutation chains

I have the following problem: I'm given a list of size $K$ of random integer permutations of $[1..n]$, named $P_1$ to $P_K$, and an additional random permutation $Q$. How hard is to find a sequence ...
6
votes
1answer
128 views

What's complexity of this set problem which looks like “Linear Programming”?

I came up with a problem below, which looks like a linear programming problem: Given $n$ sets $S_{1}, S_{2},..., S_{n}$, with constraints of : $$ \forall i=1, 2, 3,...,n\space\space \left | ...
0
votes
3answers
525 views

How can you prove that a problem is not solvable in a certain time complexity?

One of the most interesting questions in computer science is of course whether $P = NP$ or $P \neq NP$. If one wants to prove that $P \neq NP$ one can try to prove that an NPC problem is not solvable ...
32
votes
1answer
557 views

NP-Completeness of the decision problem for the generalized 15-puzzle

I am interested in the natural generalization of the famous 15-puzzle, where you have to slide blocks until you have sorted all given numbers (usally there is a gap of 1 block). Now the ...
1
vote
1answer
259 views

in SAT resolution proofs, are all DAGs possible? [closed]

these are some probably very hard but possibly significant and deep questions related to an unusual but intriguing possible "recursive" construction/formulation in SAT, with some important "structure" ...