Blocked In

Blocked Clause Decomposition

We demonstrate that it is fairly easy to decompose any propositional formula into two subsets such that both can be solved by blocked clause elimination. Such a blocked clause decomposition is useful to cheaply detect backbone variables and equivalent literals. Blocked clause decompositions are especially useful when they are unbalanced, i.e., one subset is much larger in size than the other on...

Blocked Literals Are Universal

We recently introduced a new proof system for Quantified Boolean Formulas (QBF), called QRAT, that opened up a variety of new preprocessing techniques. This paper presents a concept that follows from the QRAT proof system: blocked literals. Blocked literals are redundant universal literals that can be removed or added to clauses. We show that blocked literal elimination (BLE) and blocked litera...

Microsurgery of blocked tubes

Blocked Randomized Incremental Constructions

Randomized incremental constructions are widely used in computational geometry, but they perform very badly on large data because of their inherently random memory access patterns. We define an insertion order which removes enough randomness to significantly improve performance, but leaves enough randomness so that the algorithms remain theoretically optimal.

Blocked Clause Elimination

Boolean satisfiability (SAT) and its extensions are becoming a core technology for the analysis of systems. The SAT-based approach divides into three steps: encoding, preprocessing, and search. It is often argued that by encoding arbitrary Boolean formulas in conjunctive normal form (CNF), structural properties of the original problem are not reflected in the CNF. This should result in the fact...