Limit Theorem for a Modified Leland Hedging Strategy under Constant Transaction Costs rate

We study the Leland model for hedging portfolios in the presence of a constant proportional transaction costs coefficient. The modified Leland's strategy recently defined by the second author, contrarily to the classical one, ensures the asymptotic replication of a large class of payoff. In this setting, we prove a limit theorem for the deviation between the real portfolio and the payoff. As Pergamenshchikov did in the framework of the usual Leland's strategy, we identify the rate of convergence and the associated limit distribution. This rate turns out to be improved using the modified strategy and non periodic revision dates.Asymptotic hedging ; Leland-Lott strategy ; Transaction costs ; Martingale limit theorem.

Parabolic schemes for quasi-linear parabolic and hyperbolic PDEs via stochastic calculus

We consider two quasi-linear initial-value Cauchy problems on Rd: a parabolic system and an hyperbolic one. They both have a rst order non-linearity of the form (t; x; u) ru, a forcing term h(t; x; u) and an initial condition u0 2 L1(Rd) \ C1(Rd), where (resp. h) is smooth and locally (resp. globally) Lipschitz in u uniformly in (t; x). We prove the existence of a unique global strong solution for the parabolic system. We show the existence of a unique local strong solution for the hyperbolic one and we give a lower bound regarding its blow up time. In both cases, we do not use weak solution theory but recursive parabolic schemes studied via a stochastic approach and a regularity result for sequences of parabolic operators. The result on the hyperbolic problem is performed by means of a non-classical vanishing viscosity method

Limit Theorem for a Modified Leland Hedging Strategy under Constant Transaction Costs rate

We study the Leland model for hedging portfolios in the presence of a constant proportional transaction costs coefficient. The modified Leland's strategy recently defined by the second author, contrarily to the classical one, ensures the asymptotic replication of a large class of payoff. In this setting, we prove a limit theorem for the deviation between the real portfolio and the payoff. As Pergamenshchikov did in the framework of the usual Leland's strategy, we identify the rate of convergence and the associated limit distribution. This rate turns out to be improved using the modified strategy and non periodic revision dates

Perturbation bounds on the extremal singular values of a matrix after appending a column

In this paper, we study the perturbation of the extreme singular values of a matrix in the particular case where it is obtained after appending an arbitrary column vector. Such results have many applications in bifurcation theory, signal processing, control theory and many other fields. In the first part of this paper, we review and compare various bounds from recent research papers on this subject. We also present a new lower bound and a new upper bound on the perturbation of the operator norm is provided. Simple proofs are provided, based on the study of the characteristic polynomial rather than on variational methods, as e.g. in \cite{Li-Li}. In a second part of the paper, we present applications to signal processing and control theory

Parabolic Schemes for Quasi-Linear Parabolic and Hyperbolic PDEs Via Stochastic Calculus

International audienceWe consider two quasi-linear initial-value Cauchy problems on Rd: a parabolic system and an hyperbolic one. They both have a rst order non-linearity of the form (t; x; u) ru, a forcing term h(t; x; u) and an initial condition u0 2 L1(Rd) \ C1(Rd), where (resp. h) is smooth and locally (resp. globally) Lipschitz in u uniformly in (t; x). We prove the existence of a unique global strong solution for the parabolic system. We show the existence of a unique local strong solution for the hyperbolic one and we give a lower bound regarding its blow up time. In both cases, we do not use weak solution theory but recursive parabolic schemes studied via a stochastic approach and a regularity result for sequences of parabolic operators. The result on the hyperbolic problem is performed by means of a non-classical vanishing viscosity method

On the spacings between the successive zeros of the Laguerre polynomials

This version proposes an improved bound and more comparisons with previous worksInternational audienceWe propose a simple uniform lower bound on the spacings between the successive zeros of the Laguerre polynomials $L_n^{(\alpha)}$ for all $\alpha>-1$. Our bound is sharp regarding the order of dependency on $n$ and $\alpha$ in various ranges. In particular, we recover the orders given in \cite{ahmed} for $\alpha \in (-1,1]$

On a new method for controlling the entire spectrum in the problem of column subset selection

International audienceThe problem of extracting a well conditioned submatrix from any rectangular matrix (with normalized columns) has been studied for some time in functional and harmonic analysis. In the seminal work of Bourgain and Tzafriri and many subsequent improvements, methods using random column selection were considered. Constructive approaches have been proposed lately, mainly sparked by the work of Batson, Spielman and Srivastava. The column selection problem we consider in this paper is concerned with extracting a well conditioned submatrix, and more precisely, a matrix with all its singular values being contained in the interval [1 − ε, 1 + ε]. Such results are known to have far reaching connections with many fields in mathematics and engineering. Our main contribution is a new deterministic method that achieves the same order R for the number of selected columns as in Bourgain and Tzafriri's original Theorem, up to a log(R) multiplicative factor. Our analysis is elementary and shows how a simple eigenvalue perturbation argument can lead to an intuitive and very short proof. We also obtain individual lower and upper bounds for each singular value of the extracted matrix

Mean Square Error and Limit Theorem for the Modi fied Leland Hedging Strategy with a Constant Transaction Costs Coefficient

International audienceWe study the Leland model for hedging portfolios in the presence of a constant proportional transaction costs coefficient. The modi fied Leland's strategy defi ned in [2], contrarily to the classical one, ensures the asymptotic replication of a large class of payoff . In this setting, we prove a limit theorem for the deviation between the real portfolio and the payoff . As Pergamenshchikov did in the framework of the usual Leland's strategy [11], we identify the rate of convergence and the associated limit distribution. This rate turns out to be improved using the modi fied strategy and non periodic revision dates