Large N topological string dualities have led to a class of proposed open/closed dual-ities for superstrings. In the topological string context, the worldsheet derivation of these dualities has already been given. In this paper we take the first step in deriving the full ten-dimensional superstring dualities by showing how the dualities arise on the superstring worldsheet at the level of F term...

The structure of tree–level open and closed superstring amplitudes is analyzed. For the open superstring amplitude we find a striking and elegant form, which allows to disentangle its α–expansion into several contributions accounting for different classes of multiple zeta values. This form is bolstered by the decomposition of motivic multiple zeta values, i.e. the latter encapsulate the α–expan...

These ICTP Trieste lecture notes review the pure spinor approach to quantizing the superstring with manifest D=10 super-Poincaré invariance. The first section discusses covariant quantization of the superparticle and gives a new proof of equivalence with the Brink-Schwarz superparticle. The second section discusses the superstring in a flat background and shows how to construct vertex operators...

Based on the recent developments of explicit computations at 2 loops in superstring theory in the covariant RNS formalism, we propose an explicit formula for the arbitrary loop 4-particle amplitude in superstring theory. We prove that this formula passes two very difficult tests: modular invariance and factorization. If proved, this shows that superstring theory is not only finite order by orde...

The shortest consistent superstring problem is, given a set of positive strings and a set of negative strings, finding a shortest string including every positive string and no negative string as a substrin& This problem is NP-hard and arises in DNA sequencing by hybridization. It is also an extension of the well-known shortest cotillion superstring problem which corresponds to the case when the...

I review the theoretical expectactions for the top-quark mass in a variety of models: the Standard Model, unified models (GUTs), low-energy supersymmetric models (SUSY), unified supersymmetric models (SUSY GUTs), supergravity models, and superstring models. In all instances I consider the constraints on the top-quark mass which arise by demanding that these theories be weakly interacting. This ...

Abstract We discuss solutions of the heterotic string theory which are analogous to bosonic and superstring backgrounds related to coset conformal field theories. A class of exact ‘left-right symmetric’ solutions is obtained by supplementing the metric, antisymmetric tensor and dilaton of the superstring solutions by the gauge field background equal to the generalised Lorentz connection with to...

Problems related to string inclusion and non-inclusion have been vigorously studied in diverse fields such as data compression, molecular biology and computer security. Given a finite set of positive strings P and a finite set of negative strings N, a string α is a consistent superstring if every positive string is a substring of α and no negative string is a substring of α. The shortest (resp....

Given a collection of strings S = fs 1 ; : : : ; s n g over an alphabet , a superstring of S is a string containing each s i as a substring; that is, for each i, 1 i n, contains a block of js i j consecutive characters that match s i exactly. The shortest superstring problem is the problem of nding a superstring of minimum length. The shortest superstring problem has applications in both data c...

We study supersymmetry conditions for the heterotic pure superstring preserving and N=1 in four dimensions directly from curved superspace defined by Berkovits-Howe constraints.