<t>A libor-in-arrears swap means the floating payment made at time S is F(S,S,T) = F(S,T) (denoted L(S,T) in Lesniewski's notes). Any cashflow C made at time S has time 0 value of P(0,S)E^{Q_S}[C], which is P(0,S)E^{Q_S}[L(S,T)] in this case.The general formula for time t arbitrage-free price of cas...