American Journal of Mathematics · 1953 · 67 citations · 0 references
Natural SciencesMathematicsDifferential EquationsBoundary-value ProblemsDifference EquationsExistence TheoryInitial Value ProblemsPartial Differential EquationsSystems Of Differential EquationsDifference Equation ModelsDifference OperatorsFirst-order Difference EquationsLinear Difference EquationsLinear Initial Value ProblemsMonotone Operator Existence TheoremsMonotone Operators