Lecture Notes

Total Page:16

File Type:pdf, Size:1020Kb

Lecture Notes Lecture Notes Lars Peter Hansen October 8, 2007 2 Contents 1 Approximation Results 5 1.1 One way to Build a Stochastic Process . 5 1.2 Stationary Stochastic Process . 6 1.3 Invariant Events and the Law of Large Numbers . 6 1.4 Another Way to Build a Stochastic Process . 8 1.4.1 Stationarity . 8 1.4.2 Limiting behavior . 9 1.4.3 Ergodicity . 10 1.5 Building Nonstationary Processes . 10 1.6 Martingale Approximation . 11 3 4 CONTENTS Chapter 1 Approximation Results 1.1 One way to Build a Stochastic Process • Consider a probability space (Ω, F, P r) where Ω is a set of sample points, F is an event collection (sigma algebra) and P r assigns proba- bilities to events . • Introduce a function S :Ω → Ω such that for any event Λ, S−1(Λ) = {ω ∈ Ω: S(ω) ∈ Λ} is an event. • Introduce a (Borel measurable) measurement function x :Ω → Rn. x is a random vector. • Construct a stochastic process {Xt : t = 1, 2, ...} via the formula: t Xt(ω) = X[S (ω)] or t Xt = X ◦ S . Example 1.1.1. Let Ω be a collection of infinite sequences of real numbers. Specifically, ω = (r0, r1, ...), S(ω) = (r1, r2, ...) and x(ω) = r0. Then Xt(ω) = rt. 5 6 CHAPTER 1. APPROXIMATION RESULTS 1.2 Stationary Stochastic Process Definition 1.2.1. The transformation S is measure-preserving if: P r(Λ) = P r{S−1(Λ)} for all Λ ∈ F. Proposition 1.2.2. When S is measure-preserving, the process {Xt : t = 1, 2, ...} has identical distributions for every t. That is, the distribution func- tion for Xt is the same for all t. • Given X, form a vector X ∗ . X1 X = ... X` Apply Proposition identical to X∗ conclude that the joint distribution function for (Xt,Xt+1, ..., Xt+`) is independent of t for t = 1, 2, .... The fact that this holds any choice of ` is a equivalent to a statement that the process {Xt} is stationary. (Some people use the term strict sta- tionarity for this property.) 1.3 Invariant Events and the Law of Large Numbers Definition 1.3.1. An event Λ is invariant if Λ = S−1(Λ). Let J denote the collection of invariant events. (Like F, this event collec- tion is also a sigma algebra). We are interested in E(X|J ). If the invariant events are unions of a finite partition Λj (along with the null set), then R XdP r E(X|J )(ω) = Λj P r(Λj) The conditional expectation is constant within a partition and varies across partitions. 1.3. INVARIANT EVENTS AND THE LAW OF LARGE NUMBERS 7 There is an alternative way to think of this conditional expectation. Let H be an n-dimensional measurement function such that t Ht(ω) = H[S (ω)] is time invariant (does not depend on calendar time). Let H denote the collection of all such random vectors or measurement functions and solve the following least squares problem: min E[|X − H|2] H∈H where we now assume that E|X|2 < ∞. The solution to the least squares problem is E(X|J ). This approach does not require a finite partition, but it adds a second moment restriction. In fact there are more general measure-theoretic ways to construct this expectation. Provided that E|X| < ∞, E(X|J ) is essentially unique random variable that for any invariant event Λ satisfies: E ([X − E(X|J )]1Λ) = 0 where 1Λ is the indicator function equal to one on the set Λ and zero other- wise. Theorem 1.3.2. (Birkhoff) Suppose that S is measure preserving. i) For any X such that E|X| < ∞ T 1 X X → E(X|J ) T t t=1 with probability one; ii) for any X such that E|X|2 < ∞, T 2 1 X E X − E(x|J ) → 0. T t t=1 Definition 1.3.3. The transformation S is ergodic if all of the invariant events have probability zero or one. Lemma 1.3.4. Suppose that S is ergodic. Then EX = E(X|J ). 8 CHAPTER 1. APPROXIMATION RESULTS 1.4 Another Way to Build a Stochastic Pro- cess We may start by specifying a collection of joint distributions. Instead of specifying: X1 ∗ . X2 X = , ` ... X` ˆ specify a joint probability distribution P r`. Check and make sure that the ˆ ˆ distribution P r`+1 is consistent with P r` because both give probabilities for the events: ∗ P r{X` ∈ B} for (Borel) sets B. Then there exists a space (Ω, F, P r) and a stochastic process {Xt : t = 1, 2, ...} as in our previous construction. Kolmogorov Extension Theorem. An important application is the construction of Markov processes. Con- sider a state space E, and a transition density T (x∗|x) relative to a measure dλ. The conditional probabilities of Xt+1 given Xt,Xt−1, ...X0 are given by: T (x∗|x)dλ(x∗) when Xt = x. There is an associated conditional expectation function. Let f : E → R. For f bounded define: Z ∗ ∗ ∗ Tf(x) = E [f(xt+1)|xt = x] = f(x )T (x |x)dλ(x ) Include a marginal q0 over E, then we have constructed all of the joint dis- tributions. Iterating on T forms expectations over longer time periods (Law of Iterated Expectations): j T f(x) = E [f(xt+j)|xt = x] 1.4.1 Stationarity Definition 1.4.1. A stationary density q for a Markov process satisfies Z T (x∗|x)q(x)dλ(x) = q(x∗) 1.4. ANOTHER WAY TO BUILD A STOCHASTIC PROCESS 9 for some nonnegative q for which R q(x)dλ(x) = 1. Example 1.4.2. Suppose that T (x∗|x)q(x) = T (x|x∗)q(x∗) for some nonnegative q for which R q(x)dλ(x) = 1. Note that Z Z T (x∗|x)q(x)dλ(x) = T (x|x∗)q(x∗)dλ(x) = q(x∗). Thus q is a stationary density. When the Markov process is initialized according to a stationary den- sity, we may build the process {Xt : t = 1, 2, ...} with a measure-preserving transformation S under our first construction. 1.4.2 Limiting behavior We are interested in situations when j T f(x) → r for some r. Let q be a stationary density. Then it is necessarily true that Z Z j T f(x)q(x)dλ(x) = f(x)q(x)dλ(x) for all j. Thus Z r = fdλ(x). This may seem peculiar because so far we have not assumed that the station- ary density is unique, but we did presume that the limit point is a number and not a random variable. Apparently, if there are multiple stationary distributions, we must able to find functions f for which this limit is not constant, and indeed this is case. In fact more can be said. We may in fact find functions for which Tf = f other than the unit function. 10 CHAPTER 1. APPROXIMATION RESULTS 1.4.3 Ergodicity Associated with this stationary density, form the space of function L2 given by: Z n 2 L2 = {f : E → R : f(x) q(x)dλ(x) < ∞} Then it may be shown that T : L2 → L2. Lemma 1.4.3. Suppose that Tf = f for some f ∈ L2. Then f(Xt) is constant over time with probability one. Proof. Z Z 2 2 E [f(Xt+1)f(Xt)] = (Tf)fqdλ = f qdλ = E f(Xt) . Thus 2 E [f(Xt+1) − f(Xt)] = 0 since q is a stationary density. When the only solution to the eigenvalue equation Tf = f is a constant function (with q measure one), then we may build the process {Xt : t = 1, 2, ...} using a transformation S that is measure preserving and ergodic.1 1.5 Building Nonstationary Processes For economic applications, it is too limiting to consider only time series mod- els that are stationary. Instead we are interested in processes that display stochastic counterparts to geometric growth or arithmetic growth in loga- rithms. Let {Xt} be a stationary Markov process. 1This notion of ergodicity is relative to a measure, in this case a stationary distribution for the Markov process. When there are multiple stationary distributions, while a constant solution to the eigenvalue problem may be the only one that works for one such distribution non constant solution can exist for other stationary distributions. 1.6. MARTINGALE APPROXIMATION 11 Definition 1.5.1. If a process {Yt : t = 0, 1, ...} can be represented as: Yt+1 − Yt = κ(Xt+1,Xt), or equivalently t+1 X Yt+1 = Y0 + κ(Xj,Xj−1), j=1 then it is said to be additive. [ [ A linear combinations of two additive processes {Yt+11]} and {Yt+12]} is an additive process. Example 1.5.2. Xt+1 = AXt + BWt+1 where {Wt+1 : t = 1, 2, ...} is an iid sequence of multivariate normally dis- tributed random vectors and B has full column rank. Premultiply by B0 and obtain: 0 0 0 B Xt+1 − B Xt = B BWt+1. Then 0 −1 0 0 Wt+1 = (B B) (B Xt+1 − B AXt) . Form κ(Xt+1,Xt) = µ(Xt) + σ(Xt)Wt+1. 2 Then µ(Xt) is the conditional mean of Yt+1−Yt and |σ(Xt)| is the conditional variance. {Yt : t = 0, 1, ...} is a martingale if µ(Xt) = 0. Since σ depends on the Markov state, this is referred to as a stochastic volatility model.
Recommended publications
  • A University of Sussex Phd Thesis Available Online Via Sussex
    A University of Sussex PhD thesis Available online via Sussex Research Online: http://sro.sussex.ac.uk/ This thesis is protected by copyright which belongs to the author. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Please visit Sussex Research Online for more information and further details NON-STATIONARY PROCESSES AND THEIR APPLICATION TO FINANCIAL HIGH-FREQUENCY DATA Mailan Trinh A thesis submitted for the degree of Doctor of Philosophy University of Sussex March 2018 UNIVERSITY OF SUSSEX MAILAN TRINH A THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY NON-STATIONARY PROCESSES AND THEIR APPLICATION TO FINANCIAL HIGH-FREQUENCY DATA SUMMARY The thesis is devoted to non-stationary point process models as generalizations of the standard homogeneous Poisson process. The work can be divided in two parts. In the first part, we introduce a fractional non-homogeneous Poisson process (FNPP) by applying a random time change to the standard Poisson process. We character- ize the FNPP by deriving its non-local governing equation. We further compute moments and covariance of the process and discuss the distribution of the arrival times. Moreover, we give both finite-dimensional and functional limit theorems for the FNPP and the corresponding fractional non-homogeneous compound Poisson process. The limit theorems are derived by using martingale methods, regular vari- ation properties and Anscombe's theorem.
    [Show full text]
  • STOCHASTIC COMPARISONS and AGING PROPERTIES of an EXTENDED GAMMA PROCESS Zeina Al Masry, Sophie Mercier, Ghislain Verdier
    STOCHASTIC COMPARISONS AND AGING PROPERTIES OF AN EXTENDED GAMMA PROCESS Zeina Al Masry, Sophie Mercier, Ghislain Verdier To cite this version: Zeina Al Masry, Sophie Mercier, Ghislain Verdier. STOCHASTIC COMPARISONS AND AGING PROPERTIES OF AN EXTENDED GAMMA PROCESS. Journal of Applied Probability, Cambridge University press, 2021, 58 (1), pp.140-163. 10.1017/jpr.2020.74. hal-02894591 HAL Id: hal-02894591 https://hal.archives-ouvertes.fr/hal-02894591 Submitted on 9 Jul 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Applied Probability Trust (4 July 2020) STOCHASTIC COMPARISONS AND AGING PROPERTIES OF AN EXTENDED GAMMA PROCESS ZEINA AL MASRY,∗ FEMTO-ST, Univ. Bourgogne Franche-Comt´e,CNRS, ENSMM SOPHIE MERCIER & GHISLAIN VERDIER,∗∗ Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, LMAP, Pau, France Abstract Extended gamma processes have been seen to be a flexible extension of standard gamma processes in the recent reliability literature, for cumulative deterioration modeling purpose. The probabilistic properties of the standard gamma process have been well explored since the 1970's, whereas those of its extension remain largely unexplored. In particular, stochastic comparisons between degradation levels modeled by standard gamma processes and aging properties for the corresponding level-crossing times are nowadays well understood.
    [Show full text]
  • Arbitrage Free Approximations to Candidate Volatility Surface Quotations
    Journal of Risk and Financial Management Article Arbitrage Free Approximations to Candidate Volatility Surface Quotations Dilip B. Madan 1,* and Wim Schoutens 2,* 1 Robert H. Smith School of Business, University of Maryland, College Park, MD 20742, USA 2 Department of Mathematics, KU Leuven, 3000 Leuven, Belgium * Correspondence: [email protected] (D.B.M.); [email protected] (W.S.) Received: 19 February 2019; Accepted: 10 April 2019; Published: 21 April 2019 Abstract: It is argued that the growth in the breadth of option strikes traded after the financial crisis of 2008 poses difficulties for the use of Fourier inversion methodologies in volatility surface calibration. Continuous time Markov chain approximations are proposed as an alternative. They are shown to be adequate, competitive, and stable though slow for the moment. Further research can be devoted to speed enhancements. The Markov chain approximation is general and not constrained to processes with independent increments. Calibrations are illustrated for data on 2695 options across 28 maturities for SPY as at 8 February 2018. Keywords: bilateral gamma; fast Fourier transform; sato process; matrix exponentials JEL Classification: G10; G12; G13 1. Introduction A variety of arbitrage free models for approximating quoted option prices have been available for some time. The quotations are typically in terms of (Black and Scholes 1973; Merton 1973) implied volatilities for the traded strikes and maturities. Consequently, the set of such quotations is now popularly referred to as the volatility surface. Some of the models are nonparametric with the Dupire(1994) local volatility model being a popular example. The local volatility model is specified in terms of a deterministic function s(K, T) that expresses the local volatility for the stock if the stock were to be at level K at time T.
    [Show full text]
  • Portfolio Optimization and Option Pricing Under Defaultable Lévy
    Universit`adegli Studi di Padova Dipartimento di Matematica Scuola di Dottorato in Scienze Matematiche Indirizzo Matematica Computazionale XXVI◦ ciclo Portfolio optimization and option pricing under defaultable L´evy driven models Direttore della scuola: Ch.mo Prof. Paolo Dai Pra Coordinatore dell’indirizzo: Ch.ma Prof.ssa. Michela Redivo Zaglia Supervisore: Ch.mo Prof. Tiziano Vargiolu Universit`adegli Studi di Padova Corelatori: Ch.mo Prof. Agostino Capponi Ch.mo Prof. Andrea Pascucci Johns Hopkins University Universit`adegli Studi di Bologna Dottorando: Stefano Pagliarani To Carolina and to my family “An old man, who had spent his life looking for a winning formula (martingale), spent the last days of his life putting it into practice, and his last pennies to see it fail. The martingale is as elusive as the soul.” Alexandre Dumas Mille et un fantˆomes, 1849 Acknowledgements First and foremost, I would like to thank my supervisor Prof. Tiziano Vargiolu and my co-advisors Prof. Agostino Capponi and Prof. Andrea Pascucci, for coauthoring with me all the material appearing in this thesis. In particular, thank you to Tiziano Vargiolu for supporting me scientifically and finan- cially throughout my research and all the activities related to it. Thank you to Agostino Capponi for inviting me twice to work with him at Purdue University, and for his hospital- ity and kindness during my double stay in West Lafayette. Thank you to Andrea Pascucci for wisely leading me throughout my research during the last four years, and for giving me the chance to collaborate with him side by side, thus sharing with me his knowledge and his experience.
    [Show full text]
  • A Representation Free Quantum Stochastic Calculus
    JOURNAL OF FUNCTIONAL ANALYSIS 104, 149-197 (1992) A Representation Free Quantum Stochastic Calculus L. ACCARDI Centro Matemarico V. Volterra, Diparfimento di Matematica, Universitci di Roma II, Rome, Italy F. FACNOLA Dipartimento di Matematica, Vniversild di Trento, Povo, Italy AND J. QUAEGEBEUR Department of Mathemarics, Universiteit Leuven, Louvain, Belgium Communicated by L. Gross Received January 2; revised March 1, 1991 We develop a representation free stochastic calculus based on three inequalities (semimartingale inequality, scalar forward derivative inequality, scalar conditional variance inequality). We prove that our scheme includes all the previously developed stochastic calculi and some new examples. The abstract theory is applied to prove a Boson Levy martingale representation theorem in bounded form and a general existence, uniqueness, and unitarity theorem for quantum stochastic differential equations. 0 1992 Academic Press. Inc. 0. INTRODUCTION Stochastic calculus is a powerful tool in classical probability theory. Recently various kinds of stochastic calculi have been introduced in quan- tum probability [18, 12, 10,211. The common features of these calculi are: - One starts from a representation of the canonical commutation (or anticommutation) relations (CCR or CAR) over a space of the form L2(R+, dr; X) (where 3? is a given Hilbert space). - One introduces a family of operator valued measures on R,, related to this representation, e.g., expressed in terms of creation or annihilation or number or field operators. 149 0022-1236192 $3.00 Copyright 0 1992 by Academic Press, Inc. All rights of reproduction in any form reserved. 150 QUANTUM STOCHASTIC CALCULUS -- One shows that it is possible to develop a theory of stochastic integration with respect to these operator valued measures sufficiently rich to allow one to solve some nontrivial stochastic differential equations.
    [Show full text]
  • Normalized Random Measures Driven by Increasing Additive Processes
    The Annals of Statistics 2004, Vol. 32, No. 6, 2343–2360 DOI: 10.1214/009053604000000625 c Institute of Mathematical Statistics, 2004 NORMALIZED RANDOM MEASURES DRIVEN BY INCREASING ADDITIVE PROCESSES By Luis E. Nieto-Barajas1, Igor Prunster¨ 2 and Stephen G. Walker3 ITAM-M´exico, Universit`adegli Studi di Pavia and University of Kent This paper introduces and studies a new class of nonparamet- ric prior distributions. Random probability distribution functions are constructed via normalization of random measures driven by increas- ing additive processes. In particular, we present results for the dis- tribution of means under both prior and posterior conditions and, via the use of strategic latent variables, undertake a full Bayesian analysis. Our class of priors includes the well-known and widely used mixture of a Dirichlet process. 1. Introduction. This paper considers the problem of constructing a stochastic process, defined on the real line, which has sample paths be- having almost surely (a.s.) as a probability distribution function (d.f.). The law governing the process acts as a prior in Bayesian nonparametric prob- lems. One popular idea is to take the random probability d.f. as a normal- ized increasing process F (t)= Z(t)/Z¯, where Z¯ = limt→∞ Z(t) < +∞ (a.s.). For example, the Dirichlet process [Ferguson (1973)] arises when Z is a suitably reparameterized gamma process. We consider the case of normal- ized random d.f.s driven by an increasing additive process (IAP) L, that is, Z(t)= k(t,x) dL(x) and provide regularity conditions on k and L to ensure F is a random probability d.f.
    [Show full text]
  • A Note on Chaotic and Predictable Representations for It\^ O-Markov
    A NOTE ON CHAOTIC AND PREDICTABLE REPRESENTATIONS FOR ITO-MARKOVˆ ADDITIVE PROCESSES ZBIGNIEW PALMOWSKI, ŁUKASZ STETTNER, AND ANNA SULIMA ABSTRACT. In this paper we provide predictable and chaotic representations for Itˆo-Markov additive processes X. Such a process is governed by a finite-state CTMC J which allows one to modify the pa- rameters of the Itˆo-jump process (in so-called regime switching manner). In addition, the transition of J triggers the jump of X distributed depending on the states of J just prior to the transition. This family of processes includes Markov modulated Itˆo-L´evy processes and Markov additive processes. The derived chaotic representation of a square-integrable random variable is given as a sum of stochastic integrals with respect to some explicitly constructed orthogonal martingales. We identify the predictable representation of a square-integrable martingale as a sum of stochastic integrals of predictable processes with respect to Brownian motion and power-jumps martingales related to all the jumps appearing in the model. This re- sult generalizes the seminal result of Jacod-Yor and is of importance in financial mathematics. The derived representation then allows one to enlarge the incomplete market by a series of power-jump assets and to price all market-derivatives. KEYWORDS. Markov additive processes ⋆ martingale representation ⋆ power-jump process ⋆ orthogo- nal polynomials ⋆ stochastic integral ⋆ Brownian motion ⋆ regime switching ⋆ complete market CONTENTS 1. Introduction 2 2. Main results 3 3. Proof of predictable representation 8 3.1. Polynomial representation 8 4. Proofs of main results 13 4.1. Proof of Theorem 2 13 arXiv:1612.09216v2 [math.PR] 25 Aug 2017 4.2.
    [Show full text]
  • Financial Modeling with Volterra Processes and Applications to Options, Interest Rates and Credit Risk Sami El Rahouli
    Financial modeling with Volterra processes and applications to options, interest rates and credit risk Sami El Rahouli To cite this version: Sami El Rahouli. Financial modeling with Volterra processes and applications to options, interest rates and credit risk. Probability [math.PR]. Université de Lorraine, Université du Luxembourg, 2014. English. tel-01303063 HAL Id: tel-01303063 https://hal.archives-ouvertes.fr/tel-01303063 Submitted on 15 Apr 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Universit´ede Lorraine Universit´edu Luxembourg UFR S.T.M.I.A. et Facult´edes Sciences, de la Technologie Ecole´ Doctorale IAEM et de la Communication D.F.D. Math´ematiques These pr´esent´eele 28 f´evrier2014 pour l'obtention du doctorat de l'Universit´ede Lorraine l'Universit´edu Luxembourg Discipline Math´ematiques Discipline Math´ematiques par Sami El Rahouli Mod´elisationfinanci`ereavec des processus de Volterra et applications aux options, aux taux d'int´er^etet aux risques de cr´edit Membres du jury : Marco DOZZI Professeur `al'universit´ede Lorraine Directeur de th`ese Yuliya MISHURA Professeur `al'universit´ede Kyiv, Ukraine Rapporteur Ivan NOURDIN Professeur `al'universit´ede Lorraine Examinateur Giovanni PECCATI Professeur `al'universit´edu Luxembourg Examinateur Francesco RUSSO Professeur `al'ENSTA-ParisTech Rapporteur Anton THALMAIER Professeur `al'universit´edu Luxembourg Directeur de th`ese Contents Introduction vii 1 L´evyProcesses and Gaussian semimartingales 1 1.1 L´evyprocesses: definition .
    [Show full text]
  • A Malliavin-Skorohod Calculus in $ L^ 0$ and $ L^ 1$ for Additive And
    A Malliavin-Skorohod calculus in L0 and L1 for additive and Volterra-type processes Giulia Di Nunno∗ Josep Vives†‡ August 23, 2018 Abstract In this paper we develop a Malliavin-Skorohod type calculus for additive processes in the L0 and L1 settings, extending the probabilistic interpretation of the Malliavin-Skorohod operators to this context. We prove calculus rules and obtain a generalization of the Clark-Hausmann-Ocone formula for random variables in L1. Our theory is then applied to extend the stochastic integration with respect to volatility modulated L´evy-driven Volterra processes recently introduced in the literature. Our work yields to substantially weaker conditions that permit to cover integration with respect to e.g. Volterra processes driven by α-stable processes with α< 2. The presentation focuses on jump type processes. Keywords: Additive processes, L´evy processes, α-stable processes, Volterra processes, Malliavin- Skorohod calculus. Mathematical Subject Classification: 60H05, 60H07. 1 Introduction Malliavin-Skorohod calculus for square integrable functionals of an additive process is today a well established topic. K. Itˆoproved in [17] the so-called chaos representation property of square integrable functionals of the Brownian motion. A generalized version of this property in terms of a random measure associated to a L´evy process was proved by the same author in [18]. Later, a Malliavin- Skorohod calculus for Gaussian processes strongly based on the chaos representation property was developed. We refer the reader to [24] for the Gaussian Malliavin-Skorohod calculus. In [25] it was proved that an abstract Malliavin-Skorohod calculus could be established on any Hilbert space with Fock space structure.
    [Show full text]
  • Markovian Building Blocks for Individual-Based Modelling
    Downloaded from orbit.dtu.dk on: Sep 27, 2021 Markovian Building Blocks for Individual-Based Modelling Nilsson, Lars Anders Fredrik Publication date: 2007 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Nilsson, L. A. F. (2007). Markovian Building Blocks for Individual-Based Modelling. IMM-PHD-2008-171 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Markovian Building Blocks for Individual-Based Modelling L. A. Fredrik Nilsson Kongens Lyngby 2006 IMM-PHD-2006-XX Technical University of Denmark Informatics and Mathematical Modelling Building 321, DK-2800 Kongens Lyngby, Denmark Phone +45 45253351, Fax +45 45882673 [email protected] www.imm.dtu.dk IMM-PHD: ISSN 0909-3192 Summary The present thesis consists of a summary report, four research articles, one technical report and one manuscript. The subject of the thesis is individual- based stochastic models.
    [Show full text]
  • Dissertation
    DISSERTATION Titel der Dissertation Consistent dynamic equity market code-books from a practical point of view Verfasser Sara Karlsson angestrebter akademischer Grad Doktorin der Naturwissenschaften (Dr.rer.nat) Wien, Mai 2011 Studienkennzahl lt. Studienblatt: A 791 405 Dissertationsgebiet lt. Studienblatt: Mathematik Betreuer: Univ.-Prof. Mag. Dr. Walter Schachermayer Abstract Gebr¨auchliche Aktienpreis- bzw. Martingalmodelle beschreiben die Dy- namik des Preises einer Aktie unter einem Martingalmaß; grundlegendes Beispiel ist das Black-Scholes Modell. Im Gegensatz dazu zielt ein Markt- modell darauf ab die Dynamik eines ganzen Marktes (d.h. Aktienpreis plus abgeleitete Optionen) zu beschreiben. In der vorliegenden Arbeit besch¨aftigen wir uns mit arbitragefreien Modellen die die Dynamik eines Aktienpreises sowie flussig¨ gehandelter Derivate beschreiben. (\equity market models" respektive \market models for stock options"). Die Motivation derartige Modelle zu betrachten, liegt darin, dass eu- rop¨aische Optionen flussig¨ gehandelt werden und daher Ruckschl¨ usse¨ auf die zugrundeliegende Stochastik erlauben. Marktmodelle werden auch fur¨ Anleihen angewandt; wir verweisen auf Heath, Jarrow, and Morton[1992]. In j ungerer¨ Zeit beeinflußt dieser Zugang auch Aktienpreismodelle (siehe beispielsweise Derman and Kani [1998], Dupire[1996]). Derman und Kani schlagen vor, die dynamische Entwicklung von M¨arkten mittels Differentialgleichungen fur¨ Aktienpreis und volatility surface zu modellieren. Ein anderer Zugang wird von Sch¨onbucher[1999] gew ¨ahlt; hier ist der Ausgangspunkt die gemeinsame Dynamik von Aktienpreis und impliziten Black-Scholes Volatilit¨aten. Carmona and Nadtochiy[2009] schlagen ein Marktmodell vor, in dem der Aktienpreis als exponentieller Levy-Prozeß gegeben ist. In diesem Fall wird eine zeitinhomogene Levy-Dichte verwen- det um die zus¨atzlichen, durch Optionspreise gegebenen Informationen miteinzubeziehen.
    [Show full text]
  • A First Option Calibration of the Garch Diffusion Model by a Pde Method
    A FIRST OPTION CALIBRATION OF THE GARCH DIFFUSION MODEL BY A PDE METHOD Yiannis A. Papadopoulos1 and Alan L. Lewis2 ABSTRACT Time-series calibrations often suggest that the GARCH diffusion model could also be a suitable candidate for option (risk-neutral) calibration. But unlike the popular Heston model, it lacks a fast, semi- analytic solution for the pricing of vanilla options, perhaps the main reason why it is not used in this way. In this paper we show how an efficient finite difference-based PDE solver can effectively replace analytical solutions, enabling accurate option calibrations in less than a minute. The proposed pricing engine is shown to be robust under a wide range of model parameters and combines smoothly with black-box optimizers. We use this approach to produce a first PDE calibration of the GARCH diffusion model to SPX options and present some benchmark results for future reference. 1. Introduction Stochastic volatility models are a natural generalization of the seminal Black-Scholes-Merton (BSM) option theory. In such models, the constant volatility parameter of the BSM theory is promoted 푆 to a random process: 푑푆푡 = 푟푆푡 푑푡 + 푡 푆푡푑푊푡 . Indeed, there is general agreement in finance that 1 volatility (in its many forms) is best modelled as some sort of mean-reverting stochastic process. Starting from that premise, there are many possibilities. One of the simplest has the instantaneous 2 variance rate 푣푡 ≡ 푡 evolving as a positive diffusion process following the SDE: 푣 푣 푑푣푡 = 휅(푣̅ − 푣푡)푑푡 + 휉푣푡푑푊푡 . Here 푊푡 is an additional Brownian motion, (휅, 푣̅, 휉) > 0 are constant 푆 푣 parameters, and the two Brownian motions (푊푡 , 푊푡 ) are correlated with constant parameter .
    [Show full text]