INTRODUCTION ... xiii {sect} 1. LINEAR EQUATIONS. BASIC NOTIONS . 3 {sect} 2. EQUATIONS WITH A CLOSED OPERATOR 6 {sect} 3. THE ADJOINT EQUATION ... 10 {sect} 4. THE EQUATION ADJOINT TO THE FACTORED EQUATION. 17 {sect} 5. AN EQUATION WITH A CLOSED OPERATOR WHICH HAS A DENSE DOMAI…