Direct computation of period polynomials and classification of K3-fibred Calabi--Yau threefolds

Yuichi Enoki, Yotaro Sato, Taizan Watari

One can assign to four-dimensional N=2 supersymmetric Heterotic string vacua a set of classification invariants including a lattice ${\Lambda }_S$ and vector-valued modular forms. Some of t…