9,678 research outputs found
The Most Influential Paper Gerard Salton Never Wrote
Gerard Salton is often credited with developing the vector space model
(VSM) for information retrieval (IR). Citations to Salton give the impression
that the VSM must have been articulated as an IR model sometime between
1970 and 1975. However, the VSM as it is understood today evolved over a
longer time period than is usually acknowledged, and an articulation of the
model and its assumptions did not appear in print until several years after
those assumptions had been criticized and alternative models proposed. An
often cited overview paper titled ???A Vector Space Model for Information
Retrieval??? (alleged to have been published in 1975) does not exist, and
citations to it represent a confusion of two 1975 articles, neither of which
were overviews of the VSM as a model of information retrieval. Until the
late 1970s, Salton did not present vector spaces as models of IR generally
but rather as models of specifi c computations. Citations to the phantom
paper refl ect an apparently widely held misconception that the operational
features and explanatory devices now associated with the VSM must have
been introduced at the same time it was fi rst proposed as an IR model.published or submitted for publicatio
Bethe-Salpeter study of radially excited vector quarkonia
We solve the Bethe-Salpeter equation (BSE) for a system of a heavy
quark-antiquark pair interacting with a Poincare invariant generalization of
screened linear confining potential. In order to get reliable description the
Lorentz scalar confining interaction is complemented by the effective one gluon
exchange. Within presented model we reasonably reproduce all known radial
excitations of the vector charmonia. We have found that is the only
charmonium left bellow naive quark-antiquark threshold , while the all
excited states are situated above this threshold. We develop a method which is
enable to provide solution of full four dimensional BSE for the all excited
states. We discuss the consequences of the use of the free propagators for
calculation of excited states above the threshold. The Bethe-Salpeter string
breaking scale appears to be relatively larger then the one
defined in various potential models .Comment: typos and grammar correcte
The Stringy Representation of the D>=3 Yang-Mills Theory
I put forward the stringy representation of the 1/N strong coupling (SC)
expansion for the regularized Wilson's loop-averages in the continuous D>=3
Yang-Mills theory (YM_{D}) with a sufficiently large bare coupling constant
\lambda>\lambda_{cr} and a fixed ultraviolet cut off \Lambda. The proposed
representation is proved to provide with the confining solution of the
Dyson-Schwinger chain of the judiciously regularized U(N) Loop equations.
Building on the results obtained, we suggest the stringy pattern of the
low-energy theory associated to the D=4 U(\infty)=SU(\infty) gauge theory in
the standard \lambda=>0 phase with the asymptotic freedom in the UV domain. A
nontrivial test, to clarify whether the AdS/CFT correspondence conjecture may
be indeed applicable to the large N pure YM_{4} theory in the \lambda=>\infty
limit, is also discussed.Comment: 11 pages, the short version of hep-th/0101182, the proof (directly
from the Loop equation) of the dimensional reduction in the extreme
strong-coupling limit is additionally include
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