This review provides an introduction to non-geometric backgrounds in string theory. Starting
from a discussion of T-duality, geometric and non-geometric torus-fibrations are reviewed …

We give a general review of extended supergravities and their gauging using the duality-
covariant embedding tensor formalism. Although the focus is on four-dimensional theories …

We clarify the higher-dimensional origin of a class of dyonic gaugings of D= 4 N= 8
supergravity recently discovered, when the gauge group is chosen to be ISO (7). This …

We study the existence and stability of classical de Sitter solutions of type II supergravities
with parallel‐branes and orientifold‐planes. Together with the dilaton and volume scalar …

A bstract We classify solutions of 10d type IIA/B supergravities with orientifolds, on a 4d
maximally symmetric spacetime times a 6d group manifold. We then look for new solutions …

Classical 10d string backgrounds with a 4d de Sitter space‐time, D‐brane and orientifold
sources, are commonly believed to satisfy the following: 1. There is no classical de Sitter …

Cosmological models of the early or late universe exhibit (quasi) de Sitter space‐times with
different stability properties. Considering models derived from string theory, the swampland …

We elaborate on the construction of de Sitter solutions from IIA orientifolds of SU (3)‐
structure manifolds that solve the 10‐dimensional equations of motion at tree‐level in the …

A bstract Classical flux compactifications contribute to a well-controlled corner of the string
landscape, therefore providing an important testing ground for a variety of conjectures. We …

A bstract The α′-deformed frame-like Double Field Theory (DFT) is a T-duality and gauge
invariant extension of DFT in which generalized Green-Schwarz transformations provide a …