Unique solutions found for diffusive martingale problems.
problem Finding unique solutions to Cauchy problems for diffusive real-valued strict local martingales.
method Provided sets of smooth functions under local Hölder and Engelbert-Schmidt conditions for unique classical and weak solutions.
result Unique solutions found for specific martingale models.
Study uses viscosity solutions to solve control problems involving measure-valued martingales.
problem Stochastic control problems with measure-valued martingale state processes.
method Viscosity solution approach exploiting structural properties of MVM processes.
result Value function is the unique viscosity solution to the HJB equation.
Proves existence and uniqueness of SDE solutions with Lipschitz coefficients driven by continuous martingales.
problem Existence and uniqueness of solutions for SDEs with Lipschitz coefficients.
method Picard's iterative procedure and model-free Burkholder-Davis-Gundy inequality.
result Existence and uniqueness of solutions for SDEs with Lipschitz coefficients driven by continuous, model-free martingales.
Study finds optimal martingale coupling between two distributions with minimal entropy.
problem Finding the optimal martingale coupling between two distributions with minimal relative entropy.
method Solving a dual problem to find the log-density of the optimal coupling, which represents the marginal and martingale constraints.
result The log-density of the optimal coupling is given by a triplet of real functions representing the marginal and martingale constraints.
Geometric Bass martingales linked to Brownian motion and geometric Brownian motion.
problem Modeling continuous martingales with prescribed initial and terminal distributions.
method Developed geometric Bass martingales and established their properties.
result Explicit bijection and representation of geometric Bass martingales.
New boundary condition for Black-Scholes equations in strict local martingale models.
problem Computing prices of European options with underlying asset as a strict local martingale.
method Numerical procedure using finite difference methods with a new boundary condition at infinity.
result The minimal solution, satisfying a discrete maximum principle, is the correct derivative price.
Proposes a new consumption strategy based on martingale principles.
problem Optimizing consumption based on investment strategies without risk preferences.
method Introduces martingale consumption as a consumption pattern that adjusts to expected future consumption.
result Identifies explicit solutions in deterministic models and establishes uniqueness in general cases.
Study solves BSDEs for bond market hedging, proving convergence of strategies.
problem Approximate hedging in bond markets using BSDEs.
method Existence and uniqueness of solutions for infinite-dimensional BSDEs driven by cylindrical martingales.
result Sequence of locally risk-minimizing strategies converges to generalized hedging strategy.
Dynamic reinsurance aims to minimize surplus risk using martingale transport.
problem Minimizing surplus risk in dynamic reinsurance.
method Martingale optimal transport techniques.
result A tractable solution analogous to the Bass martingale is found.
We study the class of Azéma-Yor processes defined from a general semimartingale with a continuous running maximum process. We show that they arise as unique strong solutions of the Bachelier stochastic differential equation which we prove is equivalent to the drawdown equation. Solutions of the latter have the drawdown…
Existence of solutions to heat equation on Riemannian manifolds proven.
problem Existence of solutions to stochastic heat equations in Riemannian manifolds.
method Using Dirichlet forms on path/loop space.
result Existence of martingale solutions proven.
The paper introduces conic martingales within boundaries and provides a method to construct them.
problem Developing martingale processes within specified boundaries.
method Review and construction of martingale solutions to driftless SDEs, focusing on [0,1]. result An analytically tractable martingale with separable coefficient is identified.
The paper proves unique solutions for complex stochastic equations.
problem Stochastic equations with unbounded time horizons and jumps.
method Introduced a wellposedness result for multidimensional BSDEs with general martingales.
result Unique solutions for stochastic equations with unbounded time horizons and jumps.
Efficiently computes robust option prices using multi-marginal martingale transport.
problem Computing robust option prices under martingale constraints.
method Extending state space, sequential martingale structure, entropic regularisation.
result Fast computation of optimal solutions for large problems.
Unified framework for PE and TD methods in continuous time and space.
problem Policy evaluation and TD learning in continuous settings.
method Martingale characterization for designing PE algorithms.
result Convergent time-discretized algorithms converge to continuous-time counterparts.
Study optimal semistatic portfolios using martingale Schrödinger bridges.
problem Optimizing semistatic portfolios in a dynamic stock market.
method Minimizing entropy among calibrated martingale measures.
result Explicit solution for optimal semistatic portfolios exists.
Researchers created a continuous Markov martingale that mimics Brownian motion but lacks the strong Markov property.
problem Constructing a continuous Markov martingale with Brownian marginals that misses the strong Markov property.
method Developed a new approach to create a continuous Markov martingale that differs from Brownian motion in terms of the strong Markov property.
result A continuous Markov martingale with Brownian marginals that lacks the strong Markov property was successfully constructed.
When the underlying stock price is a strict local martingale process under an equivalent local martingale measure, Black-Scholes PDE associated with an European option may have multiple solutions. In this paper, we study an approximation for the smallest hedging price of such an European option. Our results show that a…
We discuss martingales, detrending data, and the efficient market hypothesis for stochastic processes x(t) with arbitrary diffusion coefficients D(x,t). Beginning with x-independent drift coefficients R(t) we show that Martingale stochastic processes generate uncorrelated, generally nonstationary increments. Generally,…
Solves investment, consumption, and life insurance problem with capital constraints.
problem Optimal investment, consumption, and life insurance with capital constraints.
method Martingale approach to prove existence of optimal strategy and measure, explicit solutions for power utility functions.
result Explicit solutions for optimal investment, consumption, and life insurance strategies.
We consider a class of martingales on Cartan-Hadamard manifolds that includes Brownian motion on a minimal submanifold. We give sufficient conditions for such martingales to be transient, extending previous results on the transience of minimal submanifolds. We also give conditions for the almost sure convergence of the…
Study shows how market firm capitalization models converge to stochastic PDE solutions.
problem Understanding convergence of rank-based models with common noise to stochastic PDE solutions.
method Analysis of mean field limit, martingale problem, and pathwise entropy solutions.
result Empirical cumulative distribution function converges to solution of a stochastic PDE under certain conditions.
We determine the optimal structure of couplings for the \emph{Martingale transport problem} between radially symmetric initial and terminal laws μ,ν on Rd and show the uniqueness of optimizer. Here optimality means that such solutions will minimize the functional $\E |X-Y|^p$ where 0<p≤1, and the dimensio…
Extends XVA valuation under stochastic volatility, characterizing value processes via mild solutions.
problem Valuation of contingent claims in presence of default, collateral, and funding under stochastic volatility.
method Characterizes pre-default value processes via mild solutions to parabolic semilinear PDEs under stochastic volatility.
result Characterizes pre-default value processes via mild solutions to parabolic semilinear PDEs under stochastic volatility, providing sufficient conditions for existence and uniqueness.
Defines speculative bubbles in discrete-time models based on discounted stock price losing mass.
problem Characterizing speculative bubbles in discrete-time models.
method Introduces a new definition based on discounted stock price behavior and provides probabilistic characterizations.
result Speculative bubbles in discrete time are linked to solutions of a linear Volterra integral equation.
New probabilistic approach to optimal transport using martingales.
problem Optimal transport between given distributions.
method Martingale formulation of the Benamou-Brenier problem.
result Unique solution mimics Brownian motion and provides time-consistent interpolations.
Derive derivatives of Feynman-Kac semigroups on Riemannian manifolds.
problem Analyze the derivatives of Feynman-Kac semigroups on Riemannian manifolds.
method Use local martingales and geometric assumptions to derive Bismut-type formulae and local estimates.
result Prove Bismut-type formulae for first and second derivatives of Feynman-Kac semigroups.
We determine the minimal entropy martingale measure for a general class of stochastic volatility models where both price process and volatility process contain jump terms which are correlated. This generalizes previous studies which have treated either the geometric Lévy case or continuous price processes with an ortho…
We analyze the valuation partial differential equation for European contingent claims in a general framework of stochastic volatility models where the diffusion coefficients may grow faster than linearly and degenerate on the boundaries of the state space. We allow for various types of model behavior: the volatility pr…
In this article we study an optimal stopping/optimal control problem which models the decision facing a risk-averse agent over when to sell an asset. The market is incomplete so that the asset exposure cannot be hedged. In addition to the decision over when to sell, the agent has to choose a control strategy which corr…
Investigates optimal consumption and investment strategies in non-Markovian markets with unbounded parameters.
problem Optimal consumption and investment strategies in non-Markovian markets with unbounded parameters.
method Martingale optimal principle and quadratic BSDEs with exponential moment.
result Establishes optimal strategies for consumption and investment.
Exact solutions found for a new SV model with stationary volatility.
problem Finding exact solutions for a new SV model.
method Analytical solutions for transition probability density, option values, and martingale defect.
result First example of an SV model with exact solutions, GBM volatility, and stationary volatility.
Study minimizes risk with partial data and wealth constraints.
problem Minimizing risk with partial data and wealth constraints.
method New approach using martingale representation and Clark-Ocone representation.
result Explicit solutions provided for special cases.
We consider a financial market model with a single risky asset whose price process evolves according to a general jump-diffusion with locally bounded coefficients and where market participants have only access to a partial information flow. For any utility function, we prove that the partial information financial marke…
We consider dynamic sublinear expectations (i.e., time-consistent coherent risk measures) whose scenario sets consist of singular measures corresponding to a general form of volatility uncertainty. We derive a càdlàg nonlinear martingale which is also the value process of a superhedging problem. The superhedging strate…
New swap contracts avoid bias and numerical errors, offering fair values independent of monitoring.
problem Bias and numerical integration errors in standard swap contracts.
method Characterized as solutions to a second-order system of PDEs, identified as a vector space of pay-offs.
result Existence of infinite variety of discretisation-invariant swap contracts with fair values independent of monitoring.
Optimizes portfolios with delayed economic factors.
problem Optimizing portfolios in markets with delayed economic factors.
method Maximizing power utility through QFBSDEs, verified by super-martingale argument.
result Existence and uniqueness of solutions to QFBSDEs.
Unified framework models multiple financial and insurance term structures.
problem Modeling multiple term structures in various markets.
method Extended Heath-Jarrow-Morton (HJM) approach under real-world probability.
result Characterization of local martingale deflators and existence of affine realizations.
We analyze a generalized version of the Black-Scholes equation depending on a parameter a∈(−∞,0). It satisfies the martingale condition and coincides with the Black-Scholes equation in the limit case a↗0. We show that the generalized equation is exactly solvable in terms of Hermite polynomials a…
Volterra square-root process boundary behavior and martingale measures
problem Boundary behavior of the Volterra square-root process
method Comparison principles for Volterra integral equations and generalized Riemann-Liouville fractional equations
result Finiteness of negative p-moments and atom at the boundary for rough kernels We study an optimal consumption and investment problem in a possibly incomplete market with general, not necessarily convex, stochastic constraints. We give explicit solutions for investors with exponential, logarithmic and power utility. Our approach is based on martingale methods which rely on recent results on the e…
We consider filtration consistent nonlinear expectations in probability spaces satisfying only the usual conditions and separability. Under a domination assumption, we demonstrate that these nonlinear expectations can be expressed as the solutions to Backward Stochastic Differential Equations with Lipschitz continuous …
Generalizes Bochner formula to path space for Ricci flow.
problem Characterize solutions of the Ricci flow.
method Generalizes Bochner formula to parabolic path space.
result Characterizations of the Ricci flow from Bochner inequalities.
New algorithm selects robust martingale for optimal stopping problems.
problem Optimal stopping problems in stochastic processes.
method Randomized dual martingale minimization algorithm.
result Efficiently selects Doob martingale as close as possible.
Let Q and P be equivalent probability measures and let ψ be a J-dimensional vector of random variables such that dPdQ and ψ are defined in terms of a weak solution X to a d-dimensional stochastic differential equation. Motivated by the problem of \emph{endoge…
In this paper we consider a class of BSDEs with drivers of quadratic growth, on a stochastic basis generated by continuous local martingales. We first derive the Markov property of a forward--backward system (FBSDE) if the generating martingale is a strong Markov process. Then we establish the differentiability of a FB…
Develops a martingale expansion for stochastic volatility models.
problem Approximating marginal distributions of stochastic volatility models.
method Martingale expansion framework for continuous stochastic volatility models.
result First-order perturbation expansions for small volatility-of-volatility and fast mean-reversion models.
Investigates Merton's portfolio problem in a rough stochastic environment with Volterra Heston model.
problem Optimizing investment strategies in a non-Markovian, non-semimartingale stochastic environment.
method Solves the portfolio optimization problem using the martingale optimality principle and auxiliary random process.
result Derives semi-closed form solutions for optimal strategies under power and exponential utilities.