Before revision:  We have been lead to the study of this theoretical pricing/hedging problem, by the economic significance of this type of mechanism which allows a better management of all the defaultable contract risks  respect to the standard mitigation mechanisms .
After revision:  We have been lead to the study of this theoretical pricing/hedging problem, by the economic significance of this type of mechanism which allows a better management of all the defaultable contract risks respect to the "standard" non contingent mitigation mechanisms (as full or partial collateralization) .