7,551 research outputs found
Renormalization group and divergences
Application of asymptotic freedom to the ultraviolet stability in Euclidean
quantum field theories is revisited and illustrated through the hierarchical
model making also use of a few technical developments that followed the
original works of Wilson on the renormalization group.Comment: 17 page
A Refinement Calculus for Logic Programs
Existing refinement calculi provide frameworks for the stepwise development
of imperative programs from specifications. This paper presents a refinement
calculus for deriving logic programs. The calculus contains a wide-spectrum
logic programming language, including executable constructs such as sequential
conjunction, disjunction, and existential quantification, as well as
specification constructs such as general predicates, assumptions and universal
quantification. A declarative semantics is defined for this wide-spectrum
language based on executions. Executions are partial functions from states to
states, where a state is represented as a set of bindings. The semantics is
used to define the meaning of programs and specifications, including parameters
and recursion. To complete the calculus, a notion of correctness-preserving
refinement over programs in the wide-spectrum language is defined and
refinement laws for developing programs are introduced. The refinement calculus
is illustrated using example derivations and prototype tool support is
discussed.Comment: 36 pages, 3 figures. To be published in Theory and Practice of Logic
Programming (TPLP
Logic Programming Applications: What Are the Abstractions and Implementations?
This article presents an overview of applications of logic programming,
classifying them based on the abstractions and implementations of logic
languages that support the applications. The three key abstractions are join,
recursion, and constraint. Their essential implementations are for-loops, fixed
points, and backtracking, respectively. The corresponding kinds of applications
are database queries, inductive analysis, and combinatorial search,
respectively. We also discuss language extensions and programming paradigms,
summarize example application problems by application areas, and touch on
example systems that support variants of the abstractions with different
implementations
An introduction to Graph Data Management
A graph database is a database where the data structures for the schema
and/or instances are modeled as a (labeled)(directed) graph or generalizations
of it, and where querying is expressed by graph-oriented operations and type
constructors. In this article we present the basic notions of graph databases,
give an historical overview of its main development, and study the main current
systems that implement them
Extempore: The design, implementation and application of a cyber-physical programming language
There is a long history of experimental and exploratory
programming
supported by systems that expose interaction through a
programming
language interface. These live programming systems enable
software
developers to create, extend, and modify the behaviour of
executing
software by changing source code without perceptual breaks for
recompilation. These live programming systems have taken many
forms,
but have generally been limited in their ability to express
low-level
programming concepts and the generation of efficient native
machine
code. These shortcomings have limited the effectiveness of live
programming in domains that require highly efficient numerical
processing and explicit memory management.
The most general questions addressed by this thesis are what a
systems
language designed for live programming might look like and how
such a
language might influence the development of live programming in
performance sensitive domains requiring real-time support,
direct
hardware control, or high performance computing. This thesis
answers
these questions by exploring the design, implementation and
application of Extempore, a new systems programming language,
designed specifically for live interactive programming
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