We present a novel leak detection algorithm. To prove the absence of a memory leak, the algorithm assumes its presence and runs a backward heap analysis to disprove this assumption. We have implemented this approach in a memory leak analysis tool and used it to analyze several routines that manipulate linked lists and trees. Because of the reverse nature of the algorithm, the analysis can local...

Bell's theorem reveals contradictions between the predictions of quantum mechanics and the EPR postulates for a pair of particles only in situations involving imperfect statistical correlations. However , with three or more particles, contradictions emerge even for perfect correlations. We describe an experiment which can be realized in the laboratory, using four-photon entangled states generat...

Sometimes it is pragmatically useful to prove a theorem by contradiction rather than finding a direct proof. Some reductio ad absurdum arguments have made mathematical history and the general issue if and how a proof by contradiction can be replaced by a direct proof touches upon deep foundational issues such as the legitimacy of tertium non datur arguments in classical vs. intuitionistic found...

Contract systems and hybrid type systems provide two alternative approaches for enforcing precisely-defined interface specifications, with complementary advantages: contract systems excel at blame assignment, whereas hybrid type systems support type-based static analysis. We unify these two approaches by demonstrating that hybrid type checking is sufficiently expressive to encode higher-order c...

This paper focuses on one aspect of the calculations of risk in performance assessments of the deep disposal of radioactive wastes in the UK, namely the apparent contradiction regarding the representation of microbial activity in performance assessments of the release of gases and of dissolved radionuclides. A discussion is presented of the current understanding of the microbial and chemical de...

Price dispersion in the Internet is a well studied phenomenon. It enables companies to adjust prices to a level appropriate to their strategy. This paper deals with question how Internet retailers should do so. The discussed method optimizes shortand long-term profitability by determining the exact demand curve. The method involves the application of empirical price tests. For this purpose visi...