Quantified Boolean Formula (QBF) solvers that utilize nonCNF representations are able to reason dually about conflicts and solutions by accessing structural information contained in the non-CNF representation. This structure is not as easily accessed from a CNF representation, hence CNF based solvers are not able to perform the same kind of reasoning. Recent work has shown how this additional s...

Many solvers have been designed for QBFs, the validity problem for Quantified Boolean Formulas for the past few years. In this paper, we describe a new branching heuristics whose purpose is to promote renamable Horn formulas. This heuristics is based on Hébrard’s algorithm for the recognition of such formulas. We present some experimental results obtained by our qbf solver Qbfl with the new bra...

We introduce a uniform approach of representing a variety of paraconsistent non-monotonic formalisms by quantified Boolean formulae (QBFs) in the context of four-valued semantics. This framework provides a useful platform for capturing, in a simple and natural way, a wide range of methods for preferential reasoning. Off-the-shelf QBF solvers may therefore be incorporated for simulating the corr...

Dividing a Boolean formula into smaller independent sub-formulae can be a useful technique for accelerating the solution of Boolean problems, including SAT and #SAT. Nevertheless, and despite promising early results, formula partitioning is hardly used in state-of-the-art solvers. In this paper, we show that this is rooted in a lack of consistency of the usefulness of formula partitioning techn...

Ciphertext-Policy Attribute-Based Encryption(CP-ABE) is a system for realizing complex access control on encrypted data, in which attributes are used to describe a user’s credentials and a party encrypting data determines a policy over attributes for who can decrypt. In CP-ABE schemes, access policy is attached to the ciphertext to be the input of the decryption algorithm. An access policy can ...

In this paper we present an algorithm to compute an explicit description for the difference of a semi-group Q generated by vectors in Z and its saturation Qsat. If H = Qsat \ Q is finite, we give an upper bound for the entries of h ∈ H. Finally, we present an algorithm to find all Q-minimal saturation points in Q.

Algorithms based on the enumeration of implicit hitting sets find a growing number of applications, which include maximum satisfiability and model based diagnosis, among others. This paper exploits enumeration of implicit hitting sets in the context of Quantified Boolean Formulas (QBF). The paper starts by developing a simple algorithm for QBF with two levels of quantification, which is shown t...

A certificate of satisfiability for a quantified boolean formula is a compact representation of one of its models which is used to provide solverindependent evidence of satisfiability. In addition, it can be inspected to gather explicit information about the semantics of the formula. Due to the intrinsic nature of quantified formulas, such certificates demand much care to be efficiently extract...

A Boolean formula in a conjunctive normal form is called a (k, s)-formula if every clause contains exactly k variables and every variable occurs in at most s clauses. We show that there are unsatisfiable (k, 4 · 2 k

Consider the following decision problem: for a given monotone Boolean function f decide, whether f is read-once. For this problem, it is essential how the input function f is represented. On a negative side we have the following results. Elbassioni, Makino and Rauf ([1]) proved that this problem is coNP-complete when f is given by a depth-4 read-2 monotone Boolean formula. Gurvich ([2]) proved ...