Linked from
The 48 pages that link to Boundary value problem, each with the reason it gives.
Differential equationRelated: Boundary conditions constrain solutions across an interval or region.
Harmonic functionRelated: Harmonic functions often arise as solutions determined by boundary values.
Maximum principleRelated: The principle turns boundary values into bounds throughout the domain.
Eigenvalue problemRelated: Boundary conditions select the admissible eigenvalues and eigenfunctions.