In the manual David preparted for markets and products part, on P27, 1. when Beta is 1.2, N*=32, it says that need to short 32 futures contracts. 2. Beta becomes Beta* and increases from 1.2 to 2, the optimal number of contracts is N=21.33, then long poistion on 21.33 futures contracts. I couldn't understand why in 1., the positin is short, while in 2., the position is long. I think that both of them should be in long position as both of N* and N are have "+" sign. Please help me understand this. Thanks.