39,783 research outputs found
A Hoare-like logic of asserted single-pass instruction sequences
We present a formal system for proving the partial correctness of a
single-pass instruction sequence as considered in program algebra by
decomposition into proofs of the partial correctness of segments of the
single-pass instruction sequence concerned. The system is similar to Hoare
logics, but takes into account that, by the presence of jump instructions,
segments of single-pass instruction sequences may have multiple entry points
and multiple exit points. It is intended to support a sound general
understanding of the issues with Hoare-like logics for low-level programming
languages.Comment: 22 pages, the preliminaries have textual overlaps with the
preliminaries in arXiv:1402.4950 [cs.LO] and earlier papers; introduction and
conclusions rewritten, explanatory remarks added; introduction partly
rewritten; 24 pages, clarifying examples adde
Abstract State Machines 1988-1998: Commented ASM Bibliography
An annotated bibliography of papers which deal with or use Abstract State
Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm
Robust Computer Algebra, Theorem Proving, and Oracle AI
In the context of superintelligent AI systems, the term "oracle" has two
meanings. One refers to modular systems queried for domain-specific tasks.
Another usage, referring to a class of systems which may be useful for
addressing the value alignment and AI control problems, is a superintelligent
AI system that only answers questions. The aim of this manuscript is to survey
contemporary research problems related to oracles which align with long-term
research goals of AI safety. We examine existing question answering systems and
argue that their high degree of architectural heterogeneity makes them poor
candidates for rigorous analysis as oracles. On the other hand, we identify
computer algebra systems (CASs) as being primitive examples of domain-specific
oracles for mathematics and argue that efforts to integrate computer algebra
systems with theorem provers, systems which have largely been developed
independent of one another, provide a concrete set of problems related to the
notion of provable safety that has emerged in the AI safety community. We
review approaches to interfacing CASs with theorem provers, describe
well-defined architectural deficiencies that have been identified with CASs,
and suggest possible lines of research and practical software projects for
scientists interested in AI safety.Comment: 15 pages, 3 figure
A Graph Rewriting Approach for Transformational Design of Digital Systems
Transformational design integrates design and verification. It combines âcorrectness by constructionâ and design creativity by the use of pre-proven behaviour preserving transformations as design steps. The formal aspects of this methodology are hidden in the transformations. A constraint is the availability of a design representation with a compositional formal semantics. Graph representations are useful design representations because of their visualisation of design information. In this paper graph rewriting theory, as developed in the last twenty years in mathematics, is shown to be a useful basis for a formal framework for transformational design. The semantic aspects of graphs which are no part of graph rewriting theory are included by the use of attributed graphs. The used attribute algebra, table algebra, is a relation algebra derived from database theory. The combination of graph rewriting, table algebra and transformational design is new
The Topology of Quantum Algorithms
We use a categorical topological semantics to examine the Deutsch-Jozsa,
hidden subgroup and single-shot Grover algorithms. This reveals important
structures hidden by conventional algebraic presentations, and allows novel
proofs of correctness via local topological operations, giving for the first
time a satisfying high-level explanation for why these procedures work. We also
investigate generalizations of these algorithms, providing improved analyses of
those already in the literature, and a new generalization of the single-shot
Grover algorithm.Comment: 33 pages. Updated to match the final published articl
An Algebraic Framework for Compositional Program Analysis
The purpose of a program analysis is to compute an abstract meaning for a
program which approximates its dynamic behaviour. A compositional program
analysis accomplishes this task with a divide-and-conquer strategy: the meaning
of a program is computed by dividing it into sub-programs, computing their
meaning, and then combining the results. Compositional program analyses are
desirable because they can yield scalable (and easily parallelizable) program
analyses.
This paper presents algebraic framework for designing, implementing, and
proving the correctness of compositional program analyses. A program analysis
in our framework defined by an algebraic structure equipped with sequencing,
choice, and iteration operations. From the analysis design perspective, a
particularly interesting consequence of this is that the meaning of a loop is
computed by applying the iteration operator to the loop body. This style of
compositional loop analysis can yield interesting ways of computing loop
invariants that cannot be defined iteratively. We identify a class of
algorithms, the so-called path-expression algorithms [Tarjan1981,Scholz2007],
which can be used to efficiently implement analyses in our framework. Lastly,
we develop a theory for proving the correctness of an analysis by establishing
an approximation relationship between an algebra defining a concrete semantics
and an algebra defining an analysis.Comment: 15 page
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