In this paper we present results on dynamic multivariate scalar risk measures, which arise in markets with transaction costs and systemic risk. Dual representations of such risk measures are presented. These are then used to obtain the main results of this paper on time consistency; namely, an equivalent recursive form…
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Study connects curvature bounds to map existence and flow solutions.
We consider modified scalar curvature functions for Riemannian manifolds equipped with smooth measures. Given a Riemannian submersion whose fiber transport is measure-preserving up to constants, we show that the modified scalar curvature of the base is bounded below in terms of the scalar curvatures of the total space …
In this paper we present results on scalar risk measures in markets with transaction costs. Such risk measures are defined as the minimal capital requirements in the cash asset. First, some results are provided on the dual representation of such risk measures, with particular emphasis given on the space of dual variabl…
Upper bound found for systolic geometry on manifolds with positive scalar curvature.
Synthetic scalar curvature defined via Gaussian integrals, applied to manifolds and flows.
New scalars measure failure of CC metrics to solve singular Yamabe problem.
The study examines conditions for scalar curvature and Dirac operators on singular spaces.
Study bounds on curvature for special Finsler metrics.
The paper concerns primal and dual representations as well as time consistency of set-valued dynamic risk measures. Set-valued risk measures appear naturally when markets with transaction costs are considered and capital requirements can be made in a basket of currencies or assets. Time consistency of scalar risk measu…
Extends Dirac operator results to foliations with invariant measures.
Paper studies convergence of nonnegative scalar curvature metrics to a specific limit space.
A new risk measure framework captures multivariate risk in banking.
New method removes scalar curvature assumption in Ricci flow smoothing.
Study on deformation of weighted scalar curvature, proving geometric results and stability.
Proposes new deviation measures using Minkowski gauges.
The financial crisis showed the importance of measuring, allocating and regulating systemic risk. Recently, the systemic risk measures that can be decomposed into an aggregation function and a scalar measure of risk, received a lot of attention. In this framework, capital allocations are added after aggregation and can…
The weighted Yamabe flow converges on smooth metric measure spaces.
Study shows tori metrics converging to flat under specific conditions.
Most previous contributions to BSDEs, and the related theories of nonlinear expectation and dynamic risk measures, have been in the framework of continuous time diffusions or jump diffusions. Using solutions of BSDEs on spaces related to finite state, continuous time Markov chains, we develop a theory of nonlinear expe…
Study systemic risk measures and capital allocation rules, showing commonalities.
This work extends set-valued risk measures to discrete time, using difference inclusions and equations.
A new flow method solves the weighted Yamabe problem with boundary.
Proves a conjecture about manifolds and scalar curvature.
Paper proves Gromov's conjecture on manifolds with certain group properties.
Given a closed smooth manifold M which carries a positive scalar curvature metric, one can associate an abelian group P(M) to the space of positive scalar curvature metrics on this manifold. The group of all diffeomorphisms of the manifold naturally acts on P(M). The moduli group of positive scalar curvature metrics is…
We prove a necessary and sufficient condition for an asymptotically Euclidean manifold to be conformally related to one with specified nonpositive scalar curvature: the zero set of the desired scalar curvature must have a positive Yamabe invariant, as defined in the article. We show additionally how the sign of the Yam…
Estimates scalar curvature of point clouds without embedding.
We introduce a measure for estimating the best risk-return relation of power production in wind farms within a given time-lag, conditioned to the velocity field. The velocity field is represented by a scalar that weighs the influence of the velocity at each wind turbine at present and previous time-steps for the presen…
The Riemannian Bures metric on the space of (normalized) complex positive matrices is used for parameter estimation of mixed quantum states based on repeated measurements just as the Fisher information in classical statistics. It appears also in the concept of purifications of mixed states in quantum physics. Here we d…
Prove that collapsing CSC metrics can be perturbed to invariant collapsing CSC metrics.
This paper introduces a new scalarization method for multi-objective optimization.
Study finds conditions for metrics on curved spaces.
Set-valued risk measures on with for conical market models are defined, primal and dual representation results are given. The collection of initial endowments which allow to super-hedge a multivariate claim are shown to form the values of a set-valued sublinear (coherent) risk measure. Sc…
Concrete proof that SO(n,1) is not a T-group.
Evaluation of systemic risk in networks of financial institutions in general requires information of inter-institution financial exposures. In the framework of Debt Rank algorithm, we introduce an approximate method of systemic risk evaluation which requires only node properties, such as total assets and liabilities, a…
The equivalence between multiportfolio time consistency of a dynamic multivariate risk measure and a supermartingale property is proven. Furthermore, the dual variables under which this set-valued supermartingale is a martingale are characterized as the worst-case dual variables in the dual representation of the risk m…
Consider a manifold with boundary, and such that the interior is equipped with a pseudo-Riemannian metric. We prove that, under mild asymptotic non-vanishing conditions on the scalar curvature, if the Levi-Civita connection of the interior does not extend to the boundary (because for example the interior is complete) w…
Paper proposes a new method to evaluate joint risk under uncertainty.
Let be a closed spin manifold which supports a positive scalar curvature metric. The set of concordance classes of positive scalar curvature metrics on forms an abelian group after fixing a positive scalar curvature metric. The group measures the size of the space of positive scalar curvature metr…
Conditions for scalar curvature on compact manifolds under conformal deformation.
New set-valued star-shaped risk measures introduced for better risk assessment.
The report explores conditions for positive or non-negative scalar curvature in 3-manifolds and weak Ricci curvature bounds.
Inspired by a formula of Stern that relates scalar curvature to harmonic functions, we evaluate the mass of an asymptotically flat -manifold along faces and edges of a large coordinate cube. In terms of the mean curvature and dihedral angle, the resulting mass formula relates to Gromov's scalar curvature comparison …
Choosing a portfolio of risky assets over time that maximizes the expected return at the same time as it minimizes portfolio risk is a classical problem in Mathematical Finance and is referred to as the dynamic Markowitz problem (when the risk is measured by variance) or more generally, the dynamic mean-risk problem. I…
Extends spectral torus band inequalities for compact manifolds with scalar curvature bounds.
The Positive Mass Theorem implies that any smooth, complete, asymptotically flat 3-manifold with non-negative scalar curvature which has zero total mass is isometric to (R^3, delta_{ij}). In this paper, we quantify this statement using spinors and prove that if a complete, asymptotically flat manifold with non-negative…
Set risk measures extend traditional risk measures to handle sets of positions.