“…15) where c 1,\frakq , c 1,\frakp , c 2,\frakq , and c 2,\frakp are positive constants independent of discretization and physical parameters. Following [13,27] and using Theorem 6.2 and (6.12), the condition number of \scrM D \scrA can be directly estimated as \kappa (\scrM D \scrA ) \leq \beta c 2 \gamma c 1 for c 2 = max\{ c 2,\frakq , c 2,\frakp \} and c 1 = min\{ c 1,\frakq , c 1,\frakp \} . Again, if \beta , \gamma , c 1 , and c 2 are independent of the discretization and physical parameters, then \scrM D is a robust preconditioner as well.…”