Determinism, Nondeterminism, Alternation, and Counting

Correctness and Refinement of Dually Nondeterministic Programs

In this paper we extend different reasoning methods from traditional (demonic) programs to programs with both demonic and angelic nondeterminism. In particular, we discuss correctness proofs, and refinement of programs while reducing angelic nondeterminism (into demonic nondeterminism or determinism). As expected, reducing angelic nondeterminism is generally not a refinement; however, when cont...

On determinism versus unambiquous nondeterminism for decision trees

Alternation and Bounded Concurrency Are Reverse Equivalent

Numerous models of concurrency have been considered in the framework of automata. Among the more interesting concurrency models are classical nondeterminism and pure concur-rency, the two facets of alternation, and the bounded concurrency model. Bounded concurrency was previously considered to be similar to nondeterminism and pure concurrency in the sense of the succinctness of automata augment...

Two-Way Finite Automata with a Write-Once Track

The basic finite automata model has been extended over the years with different acceptance modes (nondeterminism, alternation), new or improved devices (two-way heads, pebbles, nested pebbles) and with cooperation. None of these additions permits recognition of non-regular languages. The purpose of this work is to investigate a new kind of automata which is inspired by an extension of 2DPDAs. M...

A Type and Effect System for Determinism in Multithreaded Programs

There has been much recent interest in supporting deterministic parallelism in imperative programs. Structured parallel programming models have used type systems or static analysis to enforce determinism by constraining potential interference of lexically scoped tasks. But similar support for multithreaded programming, where threads may be ubiquitously spawned with arbitrary lifetimes, especial...