Blumenhagen, Ralph Issues of SU(5) grand unification in type IIB orientifolds. (English) Zbl 1185.81125 Prog. Theor. Phys., Suppl. 180, 135-144 (2009). Summary: We review some of the recent developements on realising grand unified theories in string theory. We explain that F-theory GUTs combine all the model building advantages of the heterotic string with a natural framework for advancing the hierarchy between the GUT and the Planck scale to a basic string model building concept. In the second more technical part some issues for the weakly couple Type IIB orientifold regime are discussed in more detail. Cited in 1 Document MSC: 81V22 Unified quantum theories Keywords:GUTs; heterotic string PDFBibTeX XMLCite \textit{R. Blumenhagen}, Prog. Theor. Phys., Suppl. 180, 135--144 (2009; Zbl 1185.81125) Full Text: DOI