sentences:  The solution is usually obtained by solving the associated free-boundary problems (Stefan problems).Let formula_23 be a Lévy diffusion in formula_24 given by the SDE
  where formula_26 is an formula_27-dimensional Brownian motion, formula_28 is an formula_29-dimensional compensated Poisson random measure, formula_30, formula_31, and formula_32 are given functions such that a unique solution formula_33 exists.Let formula_34 be an open set (the solvency region) and 
  be the bankruptcy time.