background: glass and quartz fiber posts are used in restoration of structurally compromised roots. accessory fiber posts are recently introduced to enhance the fiber post adaptation. this study evaluated the effectiveness of glass versus quartz accessory fiber posts. materials and methods: in this experimental study, 40 mandibular premolar roots with similar dimension (radius of 3.5 ± 0.2 mm a...

This paper considers efficient set mathematics for the case where the covariance matrix of asset returns is assumed known but ex ante the vector of expected returns is replaced by an estimated or forecast value. It is shown that the ex post mean and variance differ from the standard results. Consequently the maximum Sharpe ratio portfolio also differs from the standard result. However, even wit...

We consider a budget-constrained mechanism designer who selects an optimal set of projects to maximize her utility. A project’s cost is private information and its value for the designer may vary. In this allocation problem, the selection of projects both which and how many is endogenously determined by the mechanism. The designer faces ex-post constraints: The participation and budget constrai...

We investigate whether or not ex post destruction can solve the hold-up problem. After clarifying the difference between ex post destruction and nontrade when negotiation breaks down, we show that the option of ex post destruction is not sufficient to enhance ex ante efficiency. In particular, only if the information about the spitefulness of the supplier is coarse enough, will the option of ex...

This paper investigates the ex post implementation of a social choice set with two agents. A social choice set F is ex post imple-mentable with two agents if F satises the conditions of ex post incentive compatibility (EPIC) and ex post monotonicity (EM) in an environment that is economic and has a bad outcome. Furthermore, if F is a social choice function, (EPIC), (EM), and an economic environ...

We consider a general mechanism design setting where each agent can acquire (covert) information before participating in the mechanism. The central question is whether a mechanism exists which provides the efficient incentives for information acquisition ex ante and implements the efficient allocation conditional on the private information ex post. It is shown that in every private value enviro...