 It is shown that for positive values of the volatility and the risk aversion the excess rate of return above the interest rate is positive, and is monotonically increasing with respect to these variables.
<clarity>  It is shown that for positive values of the volatility and the risk aversion the excess rate of return above the interest rate is positive, and is monotonically increasing with respect to these variables.
 It is shown that for positive volatility and risk aversion the excess rate of return above the interest rate is positive, and is monotonically increasing with respect to these variables.