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Questions tagged [unique-solution]

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11 votes
1 answer
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Theorem 2.4(i) in Valiant-Vazirani paper "NP is as easy as detecting unique solutions"

I have a question about the paper "NP is as easy as detecting unique solutions" by Valiant and Vazirani, specifically the proof of the Theorem 2.4(i). The proof starts by saying Clearly, $...
deltaepsilonnn's user avatar
7 votes
0 answers
185 views

Variation of (derandomized) Valiant-Vazirani

I am interested in the following "improvement" of the Valiant-Vazirani reduction. As pointed out here, under the right derandomization assumptions one can obtain a deterministic polynomial-...
Noel Arteche's user avatar
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6 votes
0 answers
105 views

Certifying the promise in hard promise problems

Do we happen to know of any promise problems where the problem is both conditionally hard (say, NP-hard) while simultaneously being able to certify that the instance satisfies the given promise? For ...
Noel Arteche's user avatar
  • 1,049
1 vote
0 answers
165 views

Algorithms for finding unique solutions of NP-complete problems

The complexity of algorithms that find unique solution for an NP-complete problem (the input is guaranteed to have a unique solution) seems to shed light on the hardness character of different NP ...
Mohammad Al-Turkistany's user avatar
2 votes
0 answers
97 views

A question about UE

Much has been written about the class UP see related (even more in literature) example question here. Much is understood about the class UP, and its place in collapsing the PH too. UP has a played ...
user3483902's user avatar
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1 vote
1 answer
237 views

Unambiguous SAT and sparse languages

What is the consequence if there are only polynomially many 'yes' classes of instances of a language that is polynomial time reducible from a problem equivalent to UnambiguousSAT (such as possibly ...
Turbo's user avatar
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7 votes
1 answer
649 views

What's the relationship between ASP-complete and #P-complete?

Given that ASP-reductions by definition are parsimonious and parsimonious reductions preserve #P-completeness, one might think that the counting version of all ASP-complete problems are also #P-...
Jonas Kölker's user avatar
4 votes
1 answer
354 views

UnambiguousSAT reductions

Let $\Pi$ be an $\mathsf{NP}$-complete problem. It is standard that $3SAT$ and $\Pi$ are reducible from each other. Let UnambiguousSAT, or USAT for short, denote the promise problem which is 3SAT but ...
Turbo's user avatar
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19 votes
3 answers
1k views

NP-Complete problems that admit an efficient algorithm under the promise of a unique solution

I was recently reading a very nice paper by Valiant and Vazirani which shows that if $\mathbf{NP \neq RP}$, then there can not be an efficient algorithm to solve SAT even under the promise that it is ...
Devil's user avatar
  • 419
4 votes
1 answer
301 views

Evidence that UniqueSat is dense

UniqueSAT ={$\phi$| $\phi$ has unique satisfying assignment } represents an important class of computational problems. Unique SAT is CoNP-hard and $US$-complete. What is the density of UniqueSAT? ...
Mohammad Al-Turkistany's user avatar
5 votes
1 answer
1k views

Reduction from SAT to 0,1 integer linear program with zero or one solutions

Probably this is well known. There is probabilistic reduction from SAT to Unique SAT (0 or 1 solutions). According to answer and comments derandomizing the reduction would imply $PH \subseteq \oplus ...
joro's user avatar
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38 votes
4 answers
2k views

Examples where the uniqueness of the solution makes it easier to find

The complexity class $\mathsf{UP}$ consists of those $\mathsf{NP}$-problems that can be decided by a polynomial time nondeterministic Turing machine which has at most one accepting computational path. ...
Andras Farago's user avatar
19 votes
1 answer
748 views

What evidence do we have for $\mathsf{UP} \neq \mathsf{NP}$?

Following Josh Grochow's suggestion, I am converting my comment from a previous question into a new question. What evidence do we have for $\mathsf{UP} \neq \mathsf{NP}$? Here $\mathsf{UP}$ is the ...
Sasho Nikolov's user avatar
11 votes
2 answers
1k views

Does “Second X is NP-complete” imply “X is NP-complete”?

"Second $X$" problem is the problem of deciding the existence of another solution different from some given solution for problem instance. For some $NP$-complete problems, the second solution ...
Mohammad Al-Turkistany's user avatar
-2 votes
1 answer
450 views

Can every digital file have a unique fingerprint?

Disclaimer: I am not a CS person but this question is more philosophical in the sense i could not get a good enough answer ANYWHERE ELSE as to how systems such as Youtube content id work. In Youtube ...
Sandeep's user avatar
15 votes
1 answer
304 views

Does requiring uniqueness of valid answers for Merlin limit the power of Arthur-Merlin protocols?

Preamble. The complexity class AM are those problems which can be solved by a two-round interactive proof system between a prover "Merlin" and a verifier "Arthur". A problem — which tests some ...
Niel de Beaudrap's user avatar
9 votes
2 answers
988 views

Constructing uniquely satisfiable formulas

Unique SAT ={$\phi$| $\phi$ has unique satisfying assignment } represents an important class of computational problems. I recall reading that P=NP iff Unique SAT is in P (I don't remember where I read ...
Mohammad Al-Turkistany's user avatar
34 votes
2 answers
2k views

Derandomizing Valiant-Vazirani?

The Valiant-Vazirani theorem says that if there is a polynomial time algorithm (deterministic or randomized) for distinguishing between a SAT formula that has exactly one satisfying assignment, and an ...
Henry Yuen's user avatar
  • 3,888
21 votes
1 answer
1k views

Consequences of UP equals NP

EDIT at 2011/02/08: After some references finding and reading, I decided to separate the original question into two separate ones. Here's the part concerning UP vs NP, for the syntactic and semantic ...
Hsien-Chih Chang 張顯之's user avatar
21 votes
4 answers
1k views

Complexity of finding a second solution given a correct solution to an NP-complete problem

I'm looking to figure out whether there are any general results about or examples concerning the NP-completeness of the problem of finding a second solution to an NP-complete problem. More precisely, ...
Mark C.'s user avatar
  • 311
31 votes
5 answers
3k views

Verifying unique solutions of SAT

Consider the following problem: given a CNF formula and an assignment that satisfies this formula, is there another satisfying assignment for this formula ? What is the complexity of this problem ? (...
J--'s user avatar
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