10 research outputs found
Innovative Financial Securities In The Middle East: Surmounting The Ban On Interest In Islamic Law
Embedding of the Bosonic String into the String
We investigate new realisations of the algebra with arbitrary central
charge, making use of the fact that this algebra can be linearised by the
inclusion of a spin-1 current. We use the new realisations with and
to build non-critical and critical BRST operators. Both of these
can be converted by local canonical transformations into a BRST operator for
the Virasoro string with , together with a Kugo-Ojima topological term.
Consequently, these new realisations provide embeddings of the Virasoro string
into non-critical and critical strings.Comment: 11 pages. (Some referencing changes
On the Cohomology of the Noncritical -string
We investigate the cohomology structure of a general noncritical
-string. We do this by introducing a new basis in the Hilbert space in
which the BRST operator splits into a ``nested'' sum of nilpotent BRST
operators. We give explicit details for the case . In that case the BRST
operator can be written as the sum of two, mutually anticommuting,
nilpotent BRST operators: . We argue that if one chooses for the
Liouville sector a minimal model then the cohomology of the
operator is closely related to a Virasoro minimal model. In particular,
the special case of a (4,3) unitary minimal model with central charge
leads to a Ising model in the cohomology. Despite all this,
noncritical strings are not identical to noncritical Virasoro strings.Comment: 38 pages, UG-7/93, ITP-SB-93-7
A BRST Analysis of -symmetries
We perform a classical BRST analysis of the symmetries corresponding to a
generic -algebra. An essential feature of our method is that we write the
-algebra in a special basis such that the algebra manifestly has a
``nested'' set of subalgebras where the subalgebra consists of
generators of spin , respectively. In the new basis the
BRST charge can be written as a ``nested'' sum of nilpotent BRST charges.
In view of potential applications to (critical and/or non-critical) -string
theories we discuss the quantum extension of our results. In particular, we
present the quantum BRST-operator for the -algebra in the new basis. For
both critical and non-critical -strings we apply our results to discuss the
relation with minimal models.Comment: 32 pages, UG-4/9
Gravitational Duality, Branes and Charges
It is argued that D=10 type II strings and M-theory in D=11 have D-5 branes
and 9-branes that are not standard p-branes coupled to anti-symmetric tensors.
The global charges in a D-dimensional theory of gravity consist of a momentum
and a dual D-5 form charge , which is related to the
NUT charge. On dimensional reduction, P gives the electric charge and K the
magnetic charge of the graviphoton. The charge K is constructed and shown to
occur in the superalgebra and BPS bounds in , and leads to a NUT-charge
modification of the BPS bound in D=4. is carried by Kaluza-Klein monopoles,
which can be regarded as D-5 branes. Supersymmetry and U-duality imply that the
type IIB theory has (p,q) 9-branes. Orientifolding with 32 (0,1) 9-branes gives
the type I string, while modding out by a related discrete symmetry with 32
(1,0) 9-branes gives the SO(32) heterotic string. Symmetry enhancement, the
effective world-volume theories and the possibility of a twelve dimensional
origin are discussed.Comment: 54 pages, TeX, Phyzzx Macro. Added referenc
W-Gravity
The geometric structure of theories with gauge fields of spins two and higher
should involve a higher spin generalisation of Riemannian geometry. Such
geometries are discussed and the case of -gravity is analysed in
detail. While the gauge group for gravity in dimensions is the
diffeomorphism group of the space-time, the gauge group for a certain
-gravity theory (which is -gravity in the case ) is the group
of symplectic diffeomorphisms of the cotangent bundle of the space-time. Gauge
transformations for -gravity gauge fields are given by requiring the
invariance of a generalised line element. Densities exist and can be
constructed from the line element (generalising )
only if or , so that only for can actions be constructed.
These two cases and the corresponding -gravity actions are considered in
detail. In , the gauge group is effectively only a subgroup of the
symplectic diffeomorphism group. Some of the constraints that arise for
are similar to equations arising in the study of self-dual four-dimensional
geometries and can be analysed using twistor methods, allowing contact to be
made with other formulations of -gravity. While the twistor transform for
self-dual spaces with one Killing vector reduces to a Legendre transform, that
for two Killing vectors gives a generalisation of the Legendre transform.Comment: 49 pages, QMW-92-
RIAA v. Napster: A Window onto the Future of Copyright Law in the Internet Age, 18 J. Marshall J. Computer & Info. L. 755 (2000)
This article uses the Napster controversy as a stepping stone to discussing copyright law in the Internet age. Section II of the article discusses music piracy over the internet and MP3 files. Section III of the article discusses the birth of Napster and its functions. Section IV details the allegations against Napster by the RIAA. Section V. discusses Copyright Law in the digital age. Various forms of copyright infringement such as direct liability, contributory liability, vicarious liability are fully assessed. Furthermore, the author discusses the response of legislative efforts to emerging copyright challenges on the internet. Section VI examines Napter\u27s legal liability and takes a look at whether the RIAA\u27s legal claims against Napster are meritorious. Section VII. provides implications for the future in the music business and predicts how there may a shift in the future