### Orientifold reductions with fluxes and dynamical open strings

I will explain in detail how a compactification of type II string theory with orientifold planes and parallel D-branes with dynamical open strings may be effectively described by a lower-dimensional half-maximal gauged supergravity coupled to a generic number of vector multiplets. In particular, I will illustrate it explicitly in the context of orientifold reductions of type IIB down to 6d. Then I’ll sketch how this machinery can be applied to massive IIA reductions to 4d, as well. I will also discuss some preliminary results concerning 6d & 4d vacua.

**5th March 2024, 14:30**