Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
A Strictly Proper Second-Order Equation Operator is Proper
propositionprop:strictly-proper-implies-proper-2026aAnalysisPDELet be a natural number, let be an open subset of Euclidean space , let be the ordered field of real numbers, and let be a second-order equation operator on . If there exists with …Strictly Proper Second-Order Equation Operator
definitiondef:strictly-proper-operator-2026aAnalysisPDELet be a natural number, let be an open subset of Euclidean space , let be the ordered field of real numbers, let be the set of symmetric real matrices, let be a…Consistency of the Classical and Viscosity Notions for Functions of Class
corollarycor:viscosity-classical-consistency-2026bAnalysisPDEFor a degenerate elliptic operator and a function of class , the classical and viscosity notions of subsolution, supersolution and solution coincide.A Viscosity Subsolution or Supersolution of Class is Classical
propositionprop:viscosity-c2-implies-classical-2026bAnalysisPDEA viscosity subsolution or supersolution that happens to be of class satisfies the corresponding classical inequality; no ellipticity is needed.Classical Sub- and Supersolutions of a Degenerate Elliptic Operator are Viscosity Sub- and Supersolutions
propositionprop:classical-implies-viscosity-2026bAnalysisPDEFor a degenerate elliptic operator, a classical subsolution of class is a viscosity subsolution, and likewise for supersolutions.- A viscosity solution is a function that is simultaneously a viscosity subsolution and a viscosity supersolution.
Viscosity Subsolution and Supersolution of a Second-Order Equation
definitiondef:viscosity-sub-supersolution-2026cAnalysisPDEAn upper semicontinuous is a viscosity subsolution if at the data of every test function touching from above, and dually for supersolutions.- A function of class is a classical solution when vanishes at its own value, gradient and Hessian at every point.
Classical Subsolution and Supersolution of a Second-Order Equation
definitiondef:classical-sub-supersolution-2026cAnalysisPDEA function of class is a classical subsolution if pointwise at its own derivatives, and a classical supersolution if .- Let be a natural number, let be an open subset of Euclidean space , let be the set of real numbers with the order of its ordered field structure, let be the…
Degenerate Elliptic Second-Order Equation Operator
definitiondef:degenerate-elliptic-operator-2026aAnalysisPDELet be a natural number, let be an open subset of Euclidean space , let be the set of real numbers with the order of its ordered field structure, let be the…Second-Order Equation Operator on a Euclidean Open Set
definitiondef:second-order-equation-operator-2026aAnalysisPDELet be a natural number, let be an open subset of Euclidean space , let be the set of real numbers, and let be the set of symmetric real matrices. We write…