A FETI method with approximate subdomain solvers

We note that in the special case of continuous coefficients, we obtain the mul­

tiplicity scaling described in [22, Section 3]. Finally, we define a scaled jump operator by

BDr := [D ^B l1\ ... ,D ^ B l.N\

and the FETI preconditioner by

M - 1 := = BDrSBtDr. i

The matrix of the reduced linear system can be written as

Fr := Bt&B*t .