Landau-Ginzburg-Saito theory for descendant Gromov-Witten theory on projective line

We define the correlation functions for the descendants in the Landau-Ginzburg-Saito theory. We show that the correlation functions obey puncture, divisor, dilaton, and topological recursion relations. We formulate the map between the descendant observables in the GW theory on the projective line and the descendant observables in the mirror LGS theory. We prove that the LGS correlation functions of the mirror observables are equal to the GW invariants with descendants.