M(atrix) theory on an orbifold and classical two-branes therein are studied with particular emphasis to heterotic M(atrix) theory on S1=Z2 relevant to strongly coupled heterotic and dual Type IA string theories. By analyzing orbifold condition on Chan-Paton factors, we show that three choice of gauge group are possible for heterotic M(atrix) theory: SO(2N), SO(2N + 1) or USp(2N). By examining a...

acid was negatively correlated among 112 female (r 0.78), and among 74 male hop genotypes (r 0.85). Hop (Humulus lupulus L.) is a perennial, dioecious species in Additive genetic variation was detected for yield, and which the female inflorescence (cones) are harvested and used in the beer-brewing process to impart bittering and/or flavoring to beer. -acid content, cohumulone, and hop storage i...

We examine to what extent heterotic string worldsheets can describe arbitrary E8×E8 gauge fields. The traditional construction of heterotic strings builds each E8 via a Spin(16)/Z2 subgroup, typically realized as a current algebra by left-moving fermions, and as a result, only E8 gauge fields reducible to Spin(16)/Z2 gauge fields are directly realizable in standard constructions. However, there...

We consider heterotic string compactifications to four dimensions when instantons shrink to zero size. If the standard model gauge group originates from the new gauge symmetry associated with the small instantons singularity, then the weakly or strongly coupled heterotic string scales can be taken to be arbitrarily low. The SO(32) and E8×E8 gauge groups can then be very weakly coupled even at t...

We study the symmetries of the two dimensional Heterotic string theory by following the approach of Kinnersley et al for the study of stationary axially-symmetric Einstein-Maxwell equations. We identify the finite dimensional symmetries which are the analogues of the groups G and H ′ for the Einstein-Maxwell equations. We also give the constructions for the infinite number of conserved currents...

Proper symmetries act on fields while pseudo-symmetries act on both fields and coupling constants. We identify the pseudo-duality groups that act as symmetries of the equations of motion of general systems of scalar and vector fields and apply our results to N = 2, 4 and 8 supergravity theories. We present evidence that the pseudo-duality group for both the heterotic and type II strings toroida...

We review the structure D = 6, N = 1 string vacua with emphasis on the different connections due to T -dualities and S-dualities. The topics discussed include: Anomaly cancellation; K3 and orbifold D = 6, N = 1 heterotic compactifications; T -dualities between E8 × E8 and Spin(32)/Z2 heterotic vacua; non-perturbative heterotic vacua and small instantons; N = 2 TypeII/Heterotic duality in D = 4 ...