Generalities on Boundary Conditions for Equations and Systems: Introduction to Sensitive Problems

This chapter constitutes a general heuristic study of sensitive problems, and in particular of sensitive elliptic shell problems, i.e. elliptic shells clamped (or fixed) by a part Γ0 of the boundary and free by the rest Γ1. Note that such sensitive problems or “ill-posed problems”, have already been considered in general in [70], and in some very particular case of shells in [10][23][83].