An anti-maximum principle for second-order elliptic operators

Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions. I

Shmuel Agmon, Avron Douglis, Louis Nirenberg · Communications on Pure and Applied Mathematics · 1959 · 3.8K citations

Natural Sciences, Mechanical Engineering, Differential Equations +10

Fixed Point Equations and Nonlinear Eigenvalue Problems in Ordered Banach Spaces

Herbert Amann · SIAM Review · 1976 · 1.9K citations

Natural Sciences, Mathematics, Computational Mechanics +16

On the number of solutions of nonlinear equations in ordered Banach spaces

Herbert Amann · Journal of Functional Analysis · 1972 · 200 citations

Natural Sciences, Mathematics, Differential Equations +9