“…where B H is the fractional Brownian motion with Hurst index H ∈ (0, 1), and α, β and γ are positive constants. Recently this model has been used in various problems in mathematical finance, see [7,8,24]. When H = 1/2, the fractional Brownian motion is the Wiener process W , and the equation (1.1) becomes the well-known interest rate model dX t = (α − βX t ) dt + γ dW t ,…”