Review Article

Combinatorics in 𝒩 = 1 Heterotic Vacua

Table 1

A vector bundle with structure group or , respectively, breaks the group of the heterotic string into the Grand Unifying group or . The four-dimensional low-energy representation contents of arise from the branching of the 248 adjoint of under . The particle spectrum is obtained as various bundle-valued cohomology groups.

Branching of under Particle spectrum