Satisfiability (SAT) is the problem of determining whether there is a variable assignment that fulfills a given Boolean formula.

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How many satisfying assignments are there in a set of 3-CNF clauses where no clause share the same variable?

Say I have a set of 3-CNF clauses $$\mathcal{S} = \{ x_1 \vee x_2 \vee \bar{x_3}, ~~x_4 \vee x_5 \vee x_6\}$$ where $\bar{x}$ is the negation of $x$. Each variable range over $\mathbb{Z}^2$. How ...
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Is there a constant for size of disjoint clauses in 3-CNF

We are given a 3-CNF formula $\Phi$ on n variables, and a guarantee that at least $\epsilon$ fraction of $2^n$ possible assignments satisfy all clauses in $\Phi$. Now construct set $S$ of disjoint ...
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#SAT Complexity

I have been looking at algorithms for solving #SAT and calculated that simply extending a SAT algorithm like DPLL by adding the negation of a solution to the original formula and solving again takes ...
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Why is DPLL better than brute force?

I understand that by being clever about the way we navigate the search space of the SAT problem we're going to get better performance than by randomly choosing and testing solutions, though of course ...
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66 views

What complexity class is this ciruit problem?

I'm exploring an algorithm that solves k-SAT. It uses a ton of preprocessing, so I'm thinking that this will be a circuit bounds. Without knowing the runtime, I speculate on how quickly it will ...
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If one shows s that UNIQUE k-SAT is in P, does it imply P=NP?

Valiant & Vazirani proved SAT transforms UNIQUE SAT under randomized probabilistic reductions in polynomial time. Calabro et al. showed that UNIQUE k-SAT is as hard as k-SAT. Now the question is, ...
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Encoding the pigeonhole principle in CBMC

CBMC is a Bounded Model Checker for ANSI-C and C++ programs. It also supports SystemC using Scoot. It allows verifying array bounds (buffer overflows), pointer safety, ex­cep­tions and ...
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Sound and complete algorithms for boolean satifiability

To my best knowledge, these are the sound and complete algorithms for boolean satisfiability Variations of DPLL algorithm (e.g. CDCL, Look-ahead solvers) Stalmarks method Binary Decision Diagram ...
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Doesn't a formula that tests each boolean string of length $N$ force SAT to execute at least $2^N$ tests?

Since you are free to chose any formula for the SAT problem, doesn't the choice of a formula that requires a test for each subset of the group of variables force it to perform $2^N$, essentially ...
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infinite system MAX-SAT

Is there a generalization of maximal satisfaction (MAX-SAT) based on infinitely many variables? One natural occurrence of such problem is the general Ising model in material science.
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Co NP problem correponding to SAT

I've been reading lately about SAT problem, NP and co-NP. Many sources say that the SAT problem is co NP, though, I can't find a co-NP problem equivalent to SAT. Does anyone have any idea about ...
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Recipe book for SAT encodings?

SAT solvers are getting more and more efficient in solving large instances and are being used as back-ends in various contexts. Every time one wants to use them to solve a problem in a specific ...
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49 views

Satisfiability of first-order logic is undecidable?

I struggle with understanding why the satisfiability in the first-order logic is undecidable. Could you explain it with some examples? I've also seen that satisfiability in some first-order formulas ...
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What is the name of the problem? (partitioning graph into three covers)

I was wondering if this problem has a name: Given a simple graph whose edges are colored red, blue and green, $G=(V,B\cup R\cup G)$, is there a vertex-coloring $c:V\to \{B,R,G\}$ such that every edge ...
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102 views

Is finding a solution of a satisfiability problem harder than deciding satisfiability?

Is the problem of determining whether or not a given Boolean expression is satisfiable computationally distinct from actually finding a solution to the expression? In other words, is there another ...
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Detection of redundant boolean constraints

I'm trying to solve a constraint programming problem using a SAT solver. I have set of constraints in the form of propositional logic statements, which are converted to CNF using Tseitin ...
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73 views

Reduce Set problem to SAT

So the problem is, given some set $M = \{x_1,x_2,\ldots,x_n\}$ and a set of subsets $S = \{S_1, S_2, \ldots, S_m\}$ where $S_i \subseteq M$. We want to find some set $X \subseteq M$ such that $|X| \le ...
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A Reduction from XORSAT to 2-SAT

Does anyone know of a non-trivial reduction from XORSAT to 2-sat since they are both in P? (By non-trivial I mean one that does not just solve the instance of XORSAT and map it to a fixed instance of ...
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90 views

Monotone boolean satisfiability with at most k 1s is NP-Complete

I am to prove that monotone boolean formula satisfiability checking when at most k variables are set to 1 is an NP-Complete problem. Proving that it is in NP is easy, but I'm having difficulty ...
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Example for an unsatisfiable formula that can be made satisfiable by reordering quantifiers [closed]

Please give me an example of an unsatisfiable quantified 2 CNF formula. I need it in my proof and I am unable to think of one. I am looking for such an unsatisfiable quantified 2 CNF formula which ...
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Can quantified renamable Horn formulas be identified using the same procedure as unquantified formulas?

Definition: A renamable Horn formula is a Boolean formula that can be transformed into a Horn formula by flipping the polarity of every instance of one of more of its variables. Example: $\qquad ...
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Check constraint under some condition in linear programming

I would like to minimize linear pseudo-boolean function $$\mathrm{obj} = \sum_i c_i \mathrm{sel}_i$$ subject to $$\sum_i c_i sel_i \geq \mathrm{Value} \qquad\qquad(1)$$ where $c_1,\dots c_5, ...
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Why is Mixed Quantified Horn SAT in PSPACE?

I want to prove that Mixed Quantified Horn SAT is a PSPACE-complete problem. I have proved that it is PSPACE-hard. How can I prove that it is in PSPACE? My study: To prove QSAT to be in PSPACE: ...
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Why do we assume that a nondeterministic Turing machine decides a language in NP in $n^k-3$ in Sipser's proof

At page 277 of Sipser's Introduction to the Theory of Computation, a proof of the NP-completeness of SAT is given. The following comment is made on the trace of some machine $N$ which can decide a ...
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Solving SAT using tableau calculus

I've learned about tableau calculus which is a decision procedure solving the problem of satisfiability of a first order logic formula. Now I'm wondering why this technique can't be used to solve the ...
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Quantifier String Placement [closed]

This is the edited question: Suppose I have $(x_1 \vee y_1 \vee y_2)$. x is existential and y is universal. Then it should be like this in the quantifier string: $\forall y_1 \forall y_2 \exists x_1$ ...
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What is wrong with this seeming contradiction with a paper about AND-compression of SAT?

EDIT 3: Might be wrong, but I am still confused by the answer's claim "It does not have to output an instance that preserves all satisfying assignments for all the input instances". This appears to ...
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NP hard: Mixed Q Horn SAT

Prove that Mixed Quantified Horn SAT problem is NP hard by reducing the Q3SAT problem to it. Q3SAT: 3SAT with possibly universally and existentially quantified variables. Mixed Quantified Horn ...
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Does the AND-compression of SAT depends on the number of SAT instances?

From a paper An AND-compression is a deterministic polynomial-time algorithm that maps a set of SAT-instances $x_1,\dots,x_t$ to a single SAT-instance $y$ of size $poly(\max |x_i|)$ such that $y$ ...
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research on OR and AND compression in SAT formulas

this is a new/advanced paper on OR and AND compression of SAT formulas, a newer area of research that seems not covered in any textbooks so far. A simple proof that AND-compression of NP-complete ...
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NP Completeness of 3-SAT problem [closed]

I have started reading on algorithmic complexity for my thesis work. Already have studied on Polynomial time reducibility, NP-Complete, NP-Hard. Now trying to prove NP completeness of some of the ...
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Satisfiabilty 2-sat

Im trying to work out whether the following clause is satisfiable: {x, y},{x,¬y},{¬x, y},{¬x,¬y},{x, z},{x,¬z},{y, z},{y,¬z} My basic understanding is to work ...
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How can I identify that a restricted variant of Boolean SAT remains hard or not?

While I was studying SAT problem and its different instances, in Algorithms for the Satisfiability (SAT) Problem: A Survey by J. Gu et. al PDF, I came up with this variant (not mentioned there, but I ...
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210 views

3-SAT to Max-2-SAT Reduction

I'm trying to find reduction from 3-SAT to Max-2-SAT, so far no luck. Let me first describe it. 3-SAT: Given a CNF formula $\varphi$, where every clause in $\varphi$ has exactly 3 literals in ...
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Application of Combinatorics, Logic and computability theory in physical science: Tiling of Wang Tile with proportionality [closed]

The original problem of Domino Tiling and Wang Tile has great theoretical interest on computability theory... However, the great emerging problem on application of Wang Tile in material science and ...
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3SAT to CNF-SAT reduction

I am trying to prove that 3SAT is polynome time reducable to CNF-SAT, but I don't know how to do this. A formula F is in 3SAT iff f(F) is in KNFSAT, but since 3SAT is a part of KNFSAT, every formula ...
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Why is SAT in NP?

I know that CNF SAT is in NP (and also NP-complete), because SAT is in NP and NP-complete. But what I don't understand is why? Is there anyone that can explain this?
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transformation of constraint satisfaction to SAT

How can any Constraint satisfaction problem be converted to an instance of Satisfiability? I have a CSP and i know its NP hard to solve it, but i would like to convert to an instance of k-SAT, but im ...
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How to represent a 0-valid boolean formula?

I read in these two papers http://www.ccs.neu.edu/home/lieber/courses/csg260/f06/materials/papers/max-sat/p216-schaefer.pdf and http://people.csail.mit.edu/madhu/papers/noneed/fullbook.ps that if we ...
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Hardness of mixed 3-SAT and 2-SAT formula

It is well known that 3-SAT is $\sf NP$-complete , but 2-SAT is in $\sf P$. Let there be a formula with $n-1$ clauses with 2 literals each and only 1 clause with 3 literals. We can solve this ...
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Is this NP-completeness proof correct?

I want to prove that a problem $P_1$ is NP-complete. Let say that I want to do a reduction from SAT problem. If the instance of problem $P_1$ depends on $M$ and $N$, can I specify the sturcture of ...
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GSAT incompleteness example

The GSAT (Greedy Satisfiability) algorithm can be used to find a solution to a search problem encoded in CNF. I'm aware that since GSAT is greedy, it is incomplete (which means there would be cases ...
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Issue understanding the reduction of SAT to 3-SAT in poly time

Reading this http://classes.soe.ucsc.edu/cmps102/Spring10/lect/17/SAT-3SAT-and-other-red.pdf, I came to know that reducing a clause $C_i$ from a $SAT$ instance containing more than 3 literals to a ...
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Number of instances of SAT (boolean satisfiability) problems of size N?

I assume the size of an instance of the SAT problem is measured by its number of (Boolean) variables. What is total number of instances of SAT problems of size N? I guess that amounts to counting ...
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Proving 2P2N SAT is NP-Complete

I hope I named this CNF Boolean sentence the correct way. The way I see it, a 2P2N is where each literal appears twice (or at most twice, but we can say twice without loss of generality). I am ...
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Does NP-Complete imply non-satisfiability?

I've seen a lot of text concerning the first NP-Complete problem, Boolean Satisfiability. I guess I'm confused concerning the language. It sounds to me as though the problem could be difficult to ...
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What's an example of an unsatisfiable 3-CNF formula?

I'm trying to wrap my head around an NP-completeness proof which seem to revolve around SAT/3CNF-SAT. Maybe it's the late hour but I'm afraid I can't think of a 3CNF formula that cannot be satisfied ...
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Lower bound on running time for solving 3-SAT if P = NP

Is there a lower bound on the running time for solving 3-SAT if P = NP. For instance, is it known that 3-SAT can't be solved in linear time? What about quadratic?
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3-SAT problem with number of clauses equal to number of variables

Consider the 3-SAT problem where the formula is in conjunctive normal form and we restrict the Boolean formulas such that the number of clauses in the formula is equal to the number of variables. Is ...
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Complexity of calculating a single model versus all models of a propositional formula with a SAT solver

I have little background with SAT sovers and theoretical computer science. How can I describe the complexity of calculating all models of a propositional formula versus just the usual SAT problem of ...