RDP 8707: Asymmetric Information and Bid-Ask Spreads in the Eurocurrency Markets Equation

\begin{array}{l} (ii) & \frac{d σ}{d σ_{\in}^{2}} - \frac{1}{2} {[σ_{\in}^{2} + c]}^{- \frac{1}{2}} - \frac{1}{2 σ} \\ Thus \frac{dk}{d σ_{\in}^{2}} - \frac{cg (h)}{σ^{3}} [\frac{1}{1 - Rg' (h)}] + \frac{h}{2 σ} > 0 \\ since R < 1 \\ g' (h) < 1. \end{array}