Following a recent suggestion by Randall and Sundrum, we consider string compactification scenarios in which a compact slice of AdS-space arises as a subspace of the compactification manifold. A specific example is provided by the type II orientifold equivalent to type I theory on (orbifolds of) T , upon taking into account the gravitational backreaction of the D3-branes localized inside the T ...

The duality symmetry group of the cosets SU(n, 1) SU(n)⊗ U(1) , which describe the moduli space of a two-dimensional subspace of an orbifold model with (n − 1) complex Wilson lines moduli, is discussed. The full duality group and its explicit action on the moduli fields are derived. ∗ e-mail: [email protected]. 1 The derivation of a field theoretic low-energy effective action from string ...

A new approach to algorithmic computation of the homology of spaces and maps is presented. The key point of the approach is a change in the representation of sets. The proposed representation is based on a combinatorial variant of the Čech homology and the Nerve Theorem. In many situations this change of the representation of the input may help in bypassing the problems with the complexity of t...

We study Vietoris–Rips and Čech complexes of metric wedge sums and metric gluings. We show that the Vietoris–Rips (resp. Čech) complex of a wedge sum, equipped with a natural metric, is homotopy equivalent to the wedge sum of the Vietoris–Rips (resp. Čech) complexes. We also provide generalizations for certain metric gluings, i.e. when two metric spaces are glued together along a common isometr...

We discuss various dual pairs of M-theory compactifications. Each pair consists of a compactification in which the two-brane plays the central role in relation to a string theory and a compactification in which the five-brane takes center stage. We show that in many examples such dual pairs are interchanged by the same duality transformation in each case.

We derive the noncommutative torus compactification of M(atrix) theory directly from the string theory by imposing mixed boundary conditions on the membranes. The relation of various dualities in string theory and M(atrix) theory compactification on the noncommutative torus are studied.

Feature words are crucial clues for word sense disambiguation. There are two methods to select feature words: window-based and dependency-based methods. Both of them have some shortcomings, such as irrelevant noise words or paucity of feature words. In order to solve the problems of the existing methods, this paper proposes two methods to select feature words with syntactic parsing, which are b...

We study the T 5/Z2 orbifold compactification of the M-theory matrix model. This model was originally studied by Dasgupta, Mukhi, and Witten. It was found that one had to add 16 5-branes to the system to make the compactification consistent. We demonstrate how this is mimicked in the matrix model. E-mail: [email protected] E-mail: [email protected] A recent proposal by Banks, Fischler, Shenker and Suss...