부산대학교 도서관

Summary: ``We consider certain elliptic modular graph functions thatarise in the asymptotic expansion around the non-separating node ofgenus two string invariants that appear in the integrand of the$D^8\Cal R^4$ interaction in the low momentum expansion of the fourgraviton amplitude in type II superstring theory. These ellipticmodular graphs have links given by the Green function, as well itsholomorphic and anti-holomorphic derivatives. Using appropriateauxiliary graphs at various intermediate stages of the analysis, weshow that each graph can be expressed solely in terms of graphs withlinks given only by the Green function and not its derivatives. Thisresults in a reduction in the number of basis elements in the space ofelliptic modular graphs.''