Let q be the degree variable, let H be a formal variable satisfying H4=0, and define the I-function, its components I0,I1,I2,I3, the mirror map Q=qeτQ(q) with τQ(q)=I1(q)/I0(q), and the generators
Xk=dukdk(logLI0),Yk=dukdk(logL2I0I1,1),Zk=dukdk(log(q1/5L)),
where I1,1=1+qdqdτQ, L=(1−55q)−1/5, and du=Lqdq. Let F2GW(Q) denote the genus-two Gromov–Witten generating function of the quintic threefold.
Yamaguchi–Yau genus-two mirror conjecture. The function F2GW(Q) is given by
F2GW(Q)=L2I02(970X3+18575XX2+65YX2+72557X3−72629YX2−2423Y2X−24Y3+36625ZX2−9175ZYX+481441Z2X−2425Z(X2+Y2)−2883125Z2(X+Y)+4841Z2Y−144625Z3+1282233ZZ2+72547Z3).
In particular, its leading terms are
F2GW(Q)=−1445+48575Q+25125Q2+67930375Q3+O(Q4).
The paper states a main theorem proving this genus-two mirror conjecture, so the claim is solved.