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**Iterative solution of unstable variational inequalities on approximately given sets.**
*(English)*
Zbl 0932.49014

Summary: The convergence and the stability of the iterative regularization method for solving variational inequalities with bounded nonsmooth properly monotone (i.e., degenerate) operators in Banach spaces are studied. All the items of the inequality (i.e., the operator \(A\), the “right-hand side” \(f\) and the set of constraints \(\Omega\)) are to be perturbed. The connection between the parameters of regularization and perturbations which guarantee strong convergence of approximate solutions is established. In contrast to previous publications by Bruck, Reich and the first author, we do not suppose here that the approximating sequence is a priori bounded. Therefore the present results are new even for operator equations in Hilbert and Banach spaces. Apparently, the iterative processes for problems with perturbed sets of constraints are being considered for the first time.

### MSC:

49J40 | Variational inequalities |

47J20 | Variational and other types of inequalities involving nonlinear operators (general) |

65K10 | Numerical optimization and variational techniques |

47A55 | Perturbation theory of linear operators |

47H05 | Monotone operators and generalizations |

65L20 | Stability and convergence of numerical methods for ordinary differential equations |