In class we discussed the balance equation for a trading strategy Xn+1()=n()Sn+1()+(1+r)(Xn()n()Sn()) for a trading strategy (X0,(n)n=0n). This discussion was in the context of a multiperiod binomial model with parameters u,d,r where Sn+1H=uSn,Sn+1T=dSn, and r is the one period interest rate. We assumed 01. The arbitrage-free condition for this model is 0