Preface. - Introduction. -1. Exact penalty in constrained optimization. - 1.1. A sufficient condition for exact penalty in constrained optimization. - 1.2. Existence of exact penalty for inequality-constrained problems. - 1.3. Existence of exact penalty for optimization problems with mixed constraints in Banach spaces. - 1.4. Existence of exact penalty for constrained optimization problems in Hilbert spaces with smooth constraint and objective functions...