1. The problem statement, all variables and given/known data I would like to know what the definition of a Differential Eigenvalue Problem is please? I am a maths undergraduate. 2. Relevant equations \lambda y = L y, where \lambda is eigenvalue, L is a linear operator. 3. The attempt at a solution I have searched via google, encylopedia britanica, wikipedia but only have a vague understanding. If someone could help me define it that would be great. Thank you.