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Contribution Details

Type Book Chapter
Scope Discipline-based scholarship
Title Filtrations
Organization Unit
Authors
  • Delia Coculescu
  • Ashkan Nikeghbali
Editors
  • Rama Cont
Item Subtype Further Contribution (e.g. review article, editorial)
Refereed Yes
Status Published in final form
Language
  • English
Booktitle Encyclopedia of Quantitative Finance
ISBN 9780470061602
Place of Publication Chichester, UK
Publisher Wiley & Sons
Page Range 1 - 5
Date 2010
Abstract Text In this article, we define the notion of a filtration and the related notion of the usual hypotheses. We then explain the problem of enlargements of filtrations: how are (semi)martingales affected under a change of filtrations? We state the main theorems in the classical frameworks of initial and progressive enlargements of filtrations. In the case of initial enlargements of filtrations, we state the well known Jacod's condition and in the framework of progressive enlargements of filtrations, we give the decomposition of a local martingale in the larger filtration. We finally specialize to the case of immersed filtrations, which is very widely used in credit risk modeling, and study the effect of a combination of changes of filtration and probability measure in this situation.
Other Identification Number merlin-id:14834
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