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evenements:seminaireproba-math-fi [2019/12/16 21:50]
Valérie Picot
evenements:seminaireproba-math-fi [2019/12/16 21:50]
Valérie Picot
Line 8: Line 8:
 **__Exposés de l'​année 2019__ :** **__Exposés de l'​année 2019__ :**
  
-**jeudi 19 décembre à 15h00 :** <color #088A85> Miryana Grigorova</​color>​(University of Leeds) //A non-linear incomplete market model with default: Pricing of European and American options//+**jeudi 19 décembre à 15h00 :** <color #088A85> Miryana Grigorova</​color>​ (University of Leeds) //A non-linear incomplete market model with default: Pricing of European and American options//
 ++ Voir résumé |  \\ We present an incomplete market model with default which consists of one risky asset with dynamics driven by two "​sources of risk", namely a Brownian motion and a compensated default martingale. Additionally to this feature, the wealth process follows non-linear dynamics with a non-linear driver f, which allows to incorporate a number of imperfections in the market. ++ Voir résumé |  \\ We present an incomplete market model with default which consists of one risky asset with dynamics driven by two "​sources of risk", namely a Brownian motion and a compensated default martingale. Additionally to this feature, the wealth process follows non-linear dynamics with a non-linear driver f, which allows to incorporate a number of imperfections in the market.
 We thus face a non-linear incomplete market with default. ​ We provide a dual formulation of the seller'​s superhedging price for a European option in terms of the supremum, over a suitable set of equivalent probability measures Q, of the non-linear f-evaluation/​expectation under Q of the payoff. ​ We also provide some related criteria for replicability of a given pay-off. ​ By a form of symmetry, we derive corresponding results for the buyer. ​ Our results rely on first establishing a non-linear optional decomposition for processes which are (non-linear) f-strong supermartingales under Q, for all Q.  This decomposition is the analogue in our framework of the well-known optional decomposition from the linear case.  We also show that the non-linear optional decomposition is equivalent to a non-linear predictable decomposition with constraints. We thus face a non-linear incomplete market with default. ​ We provide a dual formulation of the seller'​s superhedging price for a European option in terms of the supremum, over a suitable set of equivalent probability measures Q, of the non-linear f-evaluation/​expectation under Q of the payoff. ​ We also provide some related criteria for replicability of a given pay-off. ​ By a form of symmetry, we derive corresponding results for the buyer. ​ Our results rely on first establishing a non-linear optional decomposition for processes which are (non-linear) f-strong supermartingales under Q, for all Q.  This decomposition is the analogue in our framework of the well-known optional decomposition from the linear case.  We also show that the non-linear optional decomposition is equivalent to a non-linear predictable decomposition with constraints.
evenements/seminaireproba-math-fi.txt · Last modified: 2024/05/21 07:28 by Valérie Picot

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