Dynamic portfolio strategies of a mean-variance investor are studied using Hilbert space theory, which permits a geometrical interpretation to several properties already present in Bajeux and Portait (1993). We characterize the unconstrained dynamic frontier whose slope is compared to the static case, and show hedging strategies to be buy and hold positions in the zero coupon and a portfolio of terminal value inverse to that of the numeraire portfolio.
NGUYEN, P.D. and PORTAIT, R. (1996). A Risk-return Analysis of Dynamic Portfolio Strategies with a Solvency Constraint.