## A history of Cordes condition for second order elliptic operators.(English)Zbl 0819.35029

Lions, Jacques-Louis (ed.) et al., Boundary value problems for partial differential equations and applications. Dedicated to Enrico Magenes on the occasion of his 70th birthday. Paris: Masson. Res. Notes Appl. Math. 29, 319-325 (1993).
The author studies the unique solvability of the problem $$a(x, D_{ij} u)=f\in L^ 2 (\Omega)$$ in $$H^ 2 (\Omega)\cap H^ 1_ 0 (\Omega)$$ under different conditions on $$a$$.
For the entire collection see [Zbl 0782.00097].

### MSC:

 35J15 Second-order elliptic equations 35A05 General existence and uniqueness theorems (PDE) (MSC2000)

### Keywords:

Cordes condition; unique solvability