7-branes are basic building blocks to construct models of particle physics and cosmology in type IIB string theory and F-theory. However, to achieve certain features like realistic Yukawas and de Sitter uplift terms, which are often proven insufficient, one way is to replace them by T-branes. T-branes are generalizations of 7-branes, which are embedded into the internal dimensions of the string compactification, that is described in terms of non-commuting matrices instead of functions. In this talk, the speaker will discuss the conditions for T-branes to be globally well-defined in a type IIB compactification, and in particular the obstructions to construct them. Arguably, certain no-go results challenge some of the proposals in the string phenomenology literature that involve T-branes.
