A note on the expectations hypothesis at the founding of the Fed

One of the most influential tests of the expectations hypothesis is Mankiw and Miron (1986), who found that the spread between the long-term and short-term rates provided predictive power for the short-term rate before the Fed's founding but not after. They suggested that the failure of the expectations hypothesis after the Fed's founding was due to the Fed's practice of smoothing short-term interest rates. We show that their finding that the expectations hypothesis fares better prior to the Fed's founding is due to the fact that the test they employ tends to generate results that are more favorable to the expectations hypothesis during periods when there is extreme volatility in the short-term rate. (Earlier version titled: The expectations theory and the founding of the Fed: another look at the evidence)Interest rates ; Rational expectations (Economic theory) ; Federal Reserve System - History

Virtual Segre and Verlinde numbers of projective surfaces

Recently, Marian-Oprea-Pandharipande established (a generalization of) Lehn's conjecture for Segre numbers associated to Hilbert schemes of points on surfaces. Extending work of Johnson, they provided a conjectural correspondence between Segre and Verlinde numbers. For surfaces with holomorphic 2-form, we propose conjectural generalizations of their results to moduli spaces of stable sheaves of any rank. Using Mochizuki's formula, we derive a universal function which expresses virtual Segre and Verlinde numbers of surfaces with holomorphic 2-form in terms of Seiberg-Witten invariants and intersection numbers on products of Hilbert schemes of points. We prove that certain canonical virtual Segre and Verlinde numbers of general type surfaces are topological invariants and we verify our conjectures in examples. The power series in our conjectures are algebraic functions, for which we find expressions in several cases and which are permuted under certain Galois actions. Our conjectures imply an algebraic analog of the Mari\~{n}o-Moore conjecture for higher rank Donaldson invariants. For ranks $3$ and $4$, we obtain new expressions for Donaldson invariants in terms of Seiberg-Witten invariants.Comment: Minor corrections. 38 page

You Help Me, He Helps You: Dispute Systems Design in the Sharing Economy

Kulp and Kool discuss the potential for dispute resolution schemes in a sharing economy, one they argue involves a more efficient use of resources. The sharing economy is at the nexus of fast-paced technology that connects people to previously inaccessible resources to increase local consumption. Kulp and Kool argue that such sharing economies maximize the benefits of ownership by leveraging goods and services into a resource generator allowing increased access to goods and services at a lower-than-market rate. This unique market structure requires a distinct set of laws to address the unique relationships involved, and this Article explores how attorneys can best assist in managing conflicts in a sharing economy

Verlinde formulae on complex surfaces: K-theoretic invariants

We conjecture a Verlinde type formula for the moduli space of Higgs sheaves on a surface with a holomorphic 2-form. The conjecture specializes to a Verlinde formula for the moduli space of sheaves. Our formula interpolates between $K$-theoretic Donaldson invariants studied by the first named author and Nakajima-Yoshioka and $K$-theoretic Vafa-Witten invariants introduced by Thomas and also studied by the first and second named authors. We verify our conjectures in many examples (e.g. on K3 surfaces).Comment: Published version. 37 page

Online tracking: Questioning the power of informed consent

Online tracking technologies have raised considerable concerns regarding privacy and the protection of personal data of users. In order to help users to regain control over their personal data, Europe has amended its ePrivacy directive towards an opt-in regime. There are however many open questions concerning its implementation, especially regarding the issue of informed consent. This paper explores how the new legal situation impacts on behavioral advertising practices via the storing and reading of cookies in the Netherlands. The results show that the majority of the surveyed parties involved in behavioural advertising do not inform users about the storing of cookies or the purposes of data processing of the subsequently obtained data, neither do they have obtained users' consent for the storage of cookies. We also found that the majority of users lack the skills and knowledge how to handle cookies. These findings critically question the wisdom of the informed consent regime which lies currently at the heart of Europe's ePrivacy directive. --Online behavioural advertising,profiling,cookies,informed consent,Do Not Track,ePrivacy Directive

Virtual Segre and Verlinde numbers of projective surfaces

Recently, Marian–Oprea–Pandharipande established (a generalization of) Lehn's conjecture for Segre numbers associated to Hilbert schemes of points on surfaces. Extending the work of Johnson, they provided a conjectural correspondence between Segre and Verlinde numbers. For surfaces with holomorphic 2-form, we propose conjectural generalizations of their results to moduli spaces of stable sheaves of any rank. Using Mochizuki's formula, we derive a universal function which expresses virtual Segre and Verlinde numbers of surfaces with holomorphic 2-form in terms of Seiberg–Witten invariants and intersection numbers on products of Hilbert schemes of points. We prove that certain canonical virtual Segre and Verlinde numbers of general type surfaces are topological invariants and we verify our conjectures in examples. The power series in our conjectures are algebraic functions, for which we find expressions in several cases and which are permuted under certain Galois actions. Our conjectures imply an algebraic analog of the Mariño–Moore conjecture for higher rank Donaldson invariants. For ranks 3 and 4, we obtain explicit expressions for Donaldson invariants in terms of Seiberg–Witten invariants

What Determines the Depth of BALs? Keck HIRES Observations of BALQSO 1603+300

We find that the depth and shape of the broad absorption lines (BALs) in BALQSO 1603+3002 are determined largely by the fraction of the emitting source which is covered by the BAL flow. In addition, the observed depth of the BALs is poorly correlated with their real optical depth. The implication of this result is that abundance studies based on direct extraction of column densities from the depth of the absorption troughs are unreliable. Our conclusion is based on analysis of unblended absorption features of two lines from the same ion (in this case the Si IV doublet), which allows unambiguous separation of covering factor and optical depth effects. The complex morphology of the covering factor as a function of velocity suggests that the BALs are produced by several physically separated outflows. The covering factor is ion dependent in both depth and velocity width. We also find evidence that in BALQSO 1603+3002 the flow does not cover the broad emission line region.Comment: 13 pages, 2 figures, accepted for publication in Ap