1,738 research outputs found
The Credibility of Certifiers
It is often argued that certifiers have an incentive to offer inflated certificates, although they deny it. In this paper, we study a model in which a certifier is paid by sellers, and may offer them inflated certificates, but incurs costs if doing so. We find that the certifier may
face a commitment problem: The certifier offers inflated certificates if the costs of offering the first inflated certificate are lower than the sellers' willingness-to-pay for it. However, in equilibrium, the buyers cannot be
fooled. The certifier would hence make a higher profit if the certifier did not offer inflated certificates and the buyers believed it. The number of inflated certificates, which the certifier offers in equilibrium, depends on
the costs of offering inflated certificates. Yet, the certifier may oppose an increase in the costs of offering inflated certificates. We show that whether a certifier welcomes tighter regulation or lobbies against it, may
depend on whether the new regulation only imposes higher costs, or also reduces the certifier's commitment problem significantly
The Appeal of Risky Assets
A fund's performance is usually compared to the performance of an index or other
funds. If a fund trails the benchmark, the fund manager is often replaced. We argue
that this may lead to excessive risk-taking if fund managers differ in ability and have
the opportunity to take excessive risk. To match the benchmark, fund managers may
increase the risk of their portfolio even if this decreases the expected return on the
portfolio
The Credibility of Certifiers
It is often argued that certifiers have an incentive to offer inflated certificates, although they deny it. In this paper, we study a model in which a certifier is paid by sellers, and may offer them inflated certificates, but incurs costs if doing so. We find that the certifier may face a commitment problem: The certifier offers inflated certificates if the costs of offering the first inflated certificate are lower than the sellers' willingness-to-pay for it. However, in equilibrium, the buyers cannot be fooled. The certifier would hence make a higher profit if the certifier did not offer inflated certificates and the buyers believed it. The number of inflated certificates, which the certifier offers in equilibrium, depends on the costs of offering inflated certificates. Yet, the certifier may oppose an increase in the costs of offering inflated certificates. We show that whether a certifier welcomes tighter regulation or lobbies against it, may depend on whether the new regulation only imposes higher costs, or also reduces the certifier's commitment problem significantly.Certification; commitment problem; credibility
The Appeal of Risky Assets
A fund's performance is usually compared to the performance of an index or other funds. If a fund trails the benchmark, the fund manager is often replaced. We argue that this may lead to excessive risk-taking if fund managers differ in ability and have the opportunity to take excessive risk. To match the benchmark, fund managers may increase the risk of their portfolio even if this decreases the expected return on the portfolio.Benchmarking; risk taking
The response of a 300 micron silicon detector to monoenergetic neutrons determined by the use of the Monte Carlo technique
The response of a 300 micron thick silicon detector to an incident monoenergetic neutron beam is evaluated by the Monte Carlo method for the cases of both a shielded and a bare detector. The result of Monte Carlo calculation, using elastic, inelastic, and absorption reactions indicates that the response of the silicon detector to neutrons is basically due to the elastic scattering. In addition, the gamma rays generated in the shield of the detector will result in a response which is 3 or 4 orders of magnitude smaller than response to incident photons. The response of a bare silicon detector is calculated for neutron energies up to 6 MeV and bias energies from 50 to 250 KeV. It is found that the maximum response for a 300 micron thick silicon detector is less than .004 c/n within this selected neutron and bias energy range. When the pulse height defect is introduced in the calculation the results at low energy neutrons were reduced
Orthogonally spherical objects and spherical fibrations
We introduce a relative version of the spherical objects of Seidel and
Thomas. Define an object E in the derived category D(Z x X) to be spherical
over Z if the corresponding functor from D(Z) to D(X) gives rise to
autoequivalences of D(Z) and D(X) in a certain natural way. Most known examples
come from subschemes of X fibred over Z. This categorifies to the notion of an
object of D(Z x X) orthogonal over Z. We prove that such an object is spherical
over Z if and only if it has certain cohomological properties similar to those
in the original definition of a spherical object. We then interpret this
geometrically in the case when our objects are actual flat fibrations in X over
Z.Comment: 29 pages; v2: A missing assumption reinstated in Prop. 3.7, some
notation cleaned up. The final version to appear in Adv. in Mat
On adjunctions for Fourier-Mukai transforms
We show that the adjunction counits of a Fourier–Mukai transform Φ:D(X1)→D(X2) arise from maps of the kernels of the corresponding Fourier–Mukai transforms. In a very general setting of proper separable schemes of finite type over a field we write down these maps of kernels explicitly –facilitating the computation of the twist (the cone of an adjunction counit) of Φ. We also give another description of these maps, better suited to computing cones if the kernel of Φ is a pushforward from a closed subscheme Z⊂X1×X2. Moreover, we show that we can replace the condition of properness of the ambient spaces X1 and X2 by that of Z being proper over them and still have this description apply as is. This can be used, for instance, to compute spherical twists on non-proper varieties directly and in full generality
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