Cl,apter 33: Mathematical Considerations for Index Products 651 The astute reader will notice that the above example can be generalized by drawing a three-dimensional graph. The X axis would be the price of ZYX; the Y axis would be the dollars of profit in the spread; and instead of "sliding scales," the Z axis would be the price of ABX. There is software that can draw 3-dimensional profit graphs, although they are somewhat difficult to read. The previous tables would then be horizontal planes of the three-dimensional graph. This concludes the chapter on riskless arbitrage and mathematical modeling. Recall that arbitrage in stock options can affect stock prices. The arbitrage techniques outlined here do not affect the indices themselves. That is done by the market basket hedges. It was also known that no new models are necessary for evaluation. For index options, one merely has to properly evaluate the dividend for usage in the standard Black-Scholes model. Future options can be evaluated by set­ ting the risk-free interest rate to 0% in the Black-Scholes model and discounting the result, which is the Black model. )