Reduced open Gromov-Witten invariants on K3 surfaces and multiple cover formula

In the paper, we study the wall-crossing phenomenon of reduced open Gromov-Witten invariants on K3 surfaces with rigid special Lagrangian boundary condition. As a corollary, we derived the multiple cover formula for the reduced open Gromov-Witten invariants, which is an open analog of the Gopakumar-Vafa conjecture of genus zero.