中央研究院 数學研咒所 Lattice paths a lattice path is a sequence (p(, v2).(kyg of vectors in the plane with (x1y)∈∠0×么{(0,0)}, where Z and zso are the sets of integers and nonnegative integers respective 第8页第8页 Lattice paths • A lattice path is a sequence (x1 ,y1 )(x2 ,y2 )…(xk ,yk ) of vectors in the plane with (xi ,yi )∈Z≥0×Z\{(0,0)}, where Z and Z≥0 are the sets of integers and nonnegative integers respectively