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2.
We present the development of the Lucid language from the Original Lucid of the mid-1970s to the TransLucid of today. Each
successive version of the language has been a generalisation of previous languages, but with a further understanding of the
problems at hand.
The Original Lucid (1976), originally designed for purposes of formal verification, was used to formalise the iteration in
while-loop programs. The pLucid language (1982) was used to describe dataflow networks. Indexical Lucid (1987) was introduced for
intensional programming, in which the semantics of a variable was understood as a function from a universe of possible worlds
to ordinary values. With TransLucid, and the use of contexts as firstclass values, programming can be understood in a Cartesian
framework.
相似文献
3.
Math search is a new area of research with many enabling technologies but also many challenges. Some of the enabling technologies
include XML, XPath, XQuery, and MathML. Some of the challenges involve enabling search systems to recognize mathematical symbols
and structures. Several math search projects have made considerable progress in meeting those challenges. One of the remaining
challenges is the creation and implementation of a math query language that enables the general users to express their information
needs intuitively yet precisely. This paper will present such a language and detail its features. The new math query language
offers an alternative way to describe mathematical expressions that is more consistent and less ambiguous than conventional
mathematical notation. In addition, the language goes beyond the Boolean and proximity query syntax found in standard text
search systems. It defines a powerful set of wildcards that are deemed important for math search. These wildcards provide
for more precise structural search and multi-levels of abstractions. Three new sets of wildcards and their implementation
details will also be discussed.
相似文献
4.
The dataflow language Lucid applies concepts from intensional logic to declarative ISWIM expressions which are intensionalised
relative to the dimension of time, thus introducing the notion of an expression’s history. Lucian, a language derived from
Lucid, embeds dataflow into object-orientation allowing the intensionalisation of objects. Lucian introduces the notion of
a declarative intensional object as the history of an object’s transformations. This paper discusses the embedding relationships
and semantics of conjoining the dataflow and object-oriented paradigms to provide the language Lucian for defining intensional
objects.
相似文献
5.
For 30 years the Lempel–Ziv factorization LZ
x
of a string x = x[1..n] has been a fundamental data structure of string processing, especially valuable for string compression and for computing
all the repetitions (runs) in x. Traditionally the standard method for computing LZ
x
was based on Θ(n)-time (or, depending on the measure used, O(n log n)-time) processing of the suffix tree ST
x
of x. Recently Abouelhoda et al. proposed an efficient Lempel–Ziv factorization algorithm based on an “enhanced” suffix array – that is, a suffix array SA
x
together with supporting data structures, principally an “interval tree”. In this paper we introduce a collection of fast
space-efficient algorithms for LZ factorization, also based on suffix arrays, that in theory as well as in many practical
circumstances are superior to those previously proposed; one family out of this collection achieves true Θ(n)-time alphabet-independent processing in the worst case by avoiding tree structures altogether.
The work of the first and third authors was supported in part by grants from the Natural Sciences & Engineering Research Council
of Canada. 相似文献
6.
We prove that the so-called Smoluchowski-Kramers approximation holds for a class of partial differential equations perturbed
by a non-Gaussian noisy term. Namely, we show that the solution of the one-dimensional semi-linear stochastic damped wave
equations
, u(0) = u0, ut (0) = v0, endowed with Dirichlet boundary conditions, converges as the parameter μ goes to zero to the solution of the semi-linear
stochastic heat equation
, u(0) = u0, endowed with Dirichlet boundary conditions.
Dedicated to Giuseppe Da Prato on the occasion of his 70th birthday 相似文献
7.
Angelos Charalambidis Athanasios Grivas Nikolaos S. Papaspyrou Panos Rondogiannis 《Mathematics in Computer Science》2008,2(1):123-141
The intensional transformation is a technique that can be used in order to eliminate higher-order functions from a functional program by introducing appropriate
context-manipulation operators. The transformation can be applied to a significant class of higher-order programs and results
in equivalent zero-order intensional programs that can be executed in a simple demand-driven way. Despite its simplicity, the transformation has never been seriously
evaluated with respect to its efficiency and potential. Certain simple implementations of the technique have been performed,
but questions regarding the merits of the method have remained inconclusive. In this paper we demonstrate that the transformation
can be efficiently implemented by using what we call lazy activation records, namely activation records in which some entries are filled on-demand. An evaluation of our implementation demonstrates that
the technique outperforms some of the most well-known functional programming systems, for the class of programs that can be
transformed.
This work has been partially supported by the University of Athens under the project “Kapodistrias” (grant no. 70/4/5827). 相似文献
8.
Ekkehard Krätzel 《Archiv der Mathematik》2008,91(6):518-525
The result is: The distribution of values of the enumerating function of finite, non-isomorphic abelian groups in short intervals
is similar to the distribution of square-free numbers in short intervals. Moreover, a new estimate of the error term in the
corresponding asymptotic formula is given, which improves former estimates.
相似文献
9.
Danilo Bazzanella 《Archiv der Mathematik》2008,91(2):131-135
This paper is concerned with the number of primes in short intervals. We prove that , for θ > 1/2, with the assumption of an heuristic hypothesis weaker than the Lindel?f hypothesis.
Received: 8 October 2007, Revised: 14 April 2008 相似文献
10.
Glyn Harman 《Archiv der Mathematik》2008,90(3):239-245
Let P
+(m) denote the greatest prime factor of the positive integer m. Improving and simplifying work of Dartyge [3] we show that
for . Here improves on the previous exponent .
Received: 20 April 2007 相似文献
11.
We study existence and possible uniqueness of special semihypergroups of type U on the right. In particular, we prove that there exists a unique proper semihypergroup of this kind having order 6, apart
of isomorphisms; the least order for a hypergroup of type U on the right to have a stable part which is not a subhypergroup is 9; and the minimal cardinality of a proper semihypergroup
of that kind whose heart and derived semihypergroup are proper and nontrivial is 12.
Contextually, we analyze properties of the kernel of homomorphisms g : H ↦ G, where H is a finite semihypergroup of type U on the right and G is a group. In this way, we obtain results that are immediately applicable both to the heart and to the derived of such semihypergroups.
相似文献
12.
Serge Autexier Christoph Benzmüller Dominik Dietrich Marc Wagner 《Mathematics in Computer Science》2008,2(2):253-277
Mathematical assistance systems and proof assistance systems in general have traditionally been developed as large, monolithic
systems which are often hard to maintain and extend. In this article we propose a component network architecture as a means to design and implement such systems. Under this view a mathematical assistance system is an integrated knowledge-based
system composed as a network of individual, specialized components. These components manipulate and mutually exchange different
kinds of mathematical knowledge encoded within different document formats. Consequently, several units of mathematical knowledge
coexist throughout the system within these components and this knowledge changes non-monotonically over time. Our approach
has resulted in a lean and maintainable system code and makes the system open for extensions. Moreover, it naturally decomposes
the global and complex reasoning and truth maintenance task into local reasoning and truth maintenance tasks inside the system
components. The interplay between neighboring components in the network is thereby realized by nonmonotonic updates over agreed
interface representations encoding different kinds of mathematical knowledge.
This work has been funded by the DFG Collaborative Research Center on Resource-Adaptive Cognitive Processes, SFB 378, and
was supported by grants from Studienstiftung des Deutschen Volkes e.V . 相似文献
13.
14.
Microarrays offer unprecedented possibilities for the so-called omic, e.g., genomic and proteomic, research. However, they
are also quite challenging data to analyze. The aim of this paper is to provide a short tutorial on the most common approaches
used for pattern discovery and cluster analysis as they are currently used for microarrays, in the hope to bring the attention
of the Algorithmic Community on novel aspects of classification and data analysis that deserve attention and have potential
for high reward.
R. Giancarlo is partially supported by Italian MIUR grants PRIN “Metodi Combinatori ed Algoritmici per la Scoperta di Patterns
in Biosequenze” and FIRB “Bioinformatica per la Genomica e la Proteomica” and Italy-Israel FIRB Project “Pattern Discovery
Algorithms in Discrete Structures, with Applications to Bioinformatics”. D. Scaturro is supported by a MIUR Fellowship in
the Italy-Israel FIRB Project “Pattern Discovery Algorithms in Discrete Structures, with Applications to Bioinformatics”. 相似文献
15.
Doo-Sund Lee 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2008,59(6):1069-1080
The scattering of acoustic waves by an elastic sphere in a shallow ocean wave guide is investigated taking into account the
shear waves which can exist in addition to compressional waves in scatterers of solid material. Expressions for the scattered
waves are given. Numerical values for a quantity called the farfield form function for various depth are presented in graphical
forms.
相似文献
16.
Gerd Faltings 《Milan Journal of Mathematics》2008,76(1):93-123
We show that formal groups can be used to simplify the construction of Néron models. Also we give a new proof of the stable
reduction theorem for abelian varieties.
Received: September 2007 相似文献
17.
18.
N. M. Ivochkina 《Journal of Fixed Point Theory and Applications》2008,4(1):47-56
We adapt to degenerate m-Hessian evolution equations the notion of m-approximate solutions introduced by N. Trudinger for m-Hessian elliptic equations, and we present close to necessary and sufficient conditions guaranteeing the existence and uniqueness
of such solutions for the first initial boundary value problem.
Dedicated to Professor Felix Browder 相似文献
19.
Joseph Lehec 《Archiv der Mathematik》2009,92(4):366-376
The Yao-Yao partition theorem states that for any probability measure μ on having a density which is continuous and bounded away from 0, it is possible to partition into 2n regions of equal measure for μ in such a way that every affine hyperplane of avoids at least one of the regions. We give a constructive proof of this result and extend it to slightly more general measures.
Received: 21 August 2008 相似文献
20.
Let G be a finite group, let A be a group of automorphisms of G and let CG(A) denote the subgroup of fixed points of A in G. If the order of CG(A) is coprime to the number of orbits of A in G, then CG(A) is contained in the autocommutator subgroup [G, A]. The notion of class-avoiding automorphism is used to extend theorems of J. Thompson and P. Rowley.
Received: 3 November 2008, Revised: 1 December 2008 相似文献