Demonic Joyce

Probabilistic Demonic Refinement Algebra

We propose an abstract algebra for reasoning about probabilistic programs in a total-correctness framework. In contrast to probablisitic Kleene algebra it allows genuine reasoning about total correctness and in addition to Kleene star also has a strong iteration operator. We define operators that determine whether a program is enabled, has certain failure or does not have certain failure, respe...

Demonic Testing of Concurrent Programs

Testing presents a daunting challenge for concurrent programs, as non-deterministic scheduling defeats reproducibility. The problem is even harder if, rather than testing entire systems, one tries to test individual components, for example to assess them for thread-safety. We present demonic testing, a technique combining the tangible results of unit testing with the rigour of formal rely-guara...

108-113 Joyce

Family Planning Perspectives Through the mid-1980s, Medicaid eligibility requirements included very low income thresholds established by the individual states. Between 1987 and 1991, eligibility standards for poor and near-poor pregnant women were expanded dramatically. The 1986 Omnibus Budget and Reconciliation Act (OBRA) permitted states to extend eligibility (and receive reimbursement for se...

Demonic Fixed Points

We deal with a relational model for the demonic semantics of programs. The demonic semantics of a while loop is given as a fixed point of a function involving the demonic operators. This motivates us to investigate the fixed points of these functions. We give the expression of the greatest fixed point with respect to the demonic ordering (demonic inclusion) of the semantic function. We prove th...

Joyce the Playwright