Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
Continuous n-Form, Support, and Zero Extension on a Euclidean or Half-Space Domain
definitiondef:continuous-n-form-support-euclidean-domain-2026aAnalysisMultivariable CalculusLet . We call a subset of Euclidean space an admissible domain if either is an open subset of , or is a subset of the closed upper half-space that is open in in the sense of that definition. In…Stokes Theorem for Compact Oriented Smooth Manifolds with Boundary
theoremthm:stokes-smooth-manifold-boundary-2026aAnalysisGeometryTopologyMultivariable CalculusLet with , and let be an oriented smooth manifold with boundary of dimension that is compact as defined in Smooth Atlas and Smooth Manifold with Boundary. Let be a smooth differential -form on and let denote the…Positive Compatibility of Charts on the Interior of a Smooth Manifold with Boundary
definitiondef:positive-compatibility-charts-interior-manifold-boundary-2026aGeometryTopologyMultivariable CalculusLet be a smooth manifold with boundary of dimension , and let and be charts in the chosen smooth atlas. We say that these charts are positively compatible if either or else the following conditio…Jacobian Determinant of a Differentiable Map Between Euclidean Open Sets
definitiondef:jacobian-determinant-euclidean-open-set-2026aGeometryMultivariable CalculusLet , let be open, let , and let . Suppose that is differentiable at in the sense of Differentiability at a Point and Jacobian Matrix for Maps Between Euclidean Spaces, so that the Jacobian matrix…Determinant of a Real Square Matrix
definitiondef:determinant-real-square-matrix-2026aLinear AlgebraMultivariable CalculusLet , and let be an real matrix. The determinant of is the real number where is the set of permutations from…Smooth Map on an Open Subset of Euclidean Space
definitiondef:smooth-map-euclidean-open-set-2026aMultivariable CalculusLet , let be open, and let . We say that is smooth on if for every multi-index of length and every index , the partial derivative of of order exi…Partial Derivative of Order
definitiondef:partial-derivative-order-alpha-2026aMultivariable CalculusLet , let be open, let , and let be a multi-index of length . We define recursively what it means for the partial derivative of of order to exist on , and when it…Order and Factorial of a Multi-Index
definitiondef:order-factorial-multi-index-2026aCombinatoricsMultivariable CalculusLet , and let be a multi-index of length in the sense of Multi-Index of Length . The order of is the nonnegative integer The factorial of is the natural number…- Let . A multi-index of length is an element That is, a multi-index of length is an ordered -tuple of nonnegative integers. The zero multi-index of length is For e…
Interior Points, Boundary Points, and Boundary of a Smooth Manifold with Boundary
definitiondef:boundary-smooth-manifold-with-boundary-2026aGeometryTopologyMultivariable CalculusLet be a smooth manifold with boundary of dimension in the sense of Smooth Atlas and Smooth Manifold with Boundary, and let . We say that is an interior point of if there exists a chart in the chosen atlas with and…Smooth Atlas and Smooth Manifold with Boundary
definitiondef:smooth-manifold-with-boundary-2026aGeometryTopologyMultivariable CalculusLet be a topological space, and let . A smooth atlas of dimension on , modeled on the closed upper half-space, is a family of charts for some set such that the follo…Smooth Compatibility of Charts Modeled on the Closed Upper Half-Space
definitiondef:smooth-compatible-charts-upper-half-space-2026aGeometryTopologyMultivariable CalculusLet be a topological space, let , and let and be charts of dimension on in the sense of Chart Modeled on the Closed Upper Half-Space. Write…Chart Modeled on the Closed Upper Half-Space
definitiondef:chart-upper-half-space-2026aGeometryTopologyMultivariable CalculusLet be a topological space, let , and let . A chart of dimension on , modeled on the closed upper half-space, is a pair with the following properties. 1. . 2. If denotes the half-space fr…Closed Upper Half-Space in Euclidean Space
definitiondef:closed-upper-half-space-euclidean-2026aGeometryTopologyMultivariable CalculusLet . In the Euclidean space , the closed upper half-space is the subset A subset is said to be open in if there exists an open subset suc…- Let , and let . Then the following are equivalent. 1. is compact in , where is regarded as a topological space through the topology determined by the Euclidean distance. 2. is closed in a…
Compact Subset of is Closed
theoremthm:compact-subset-rn-closed-2026aAnalysisTopologyMultivariable CalculusLet , and let . Assume that is compact in , where is regarded as a topological space through the topology determined by the Euclidean distance. Then is closed in .Compact Subset of is Bounded
theoremthm:compact-subset-rn-bounded-2026aAnalysisTopologyMultivariable CalculusLet , and let . Assume that is compact in , where is regarded as a topological space through the topology determined by the Euclidean distance. Then is bounded as a subset of the metric space…Closed Box in is Compact
theoremthm:closed-box-compact-rn-2026aAnalysisTopologyMultivariable CalculusLet . For each index , let satisfy , and let be the closed box determined by these endpoints. Then is compact in , where is regarded as a topological sp…Euclidean Open Box Criterion in
theoremthm:euclidean-open-box-criterion-rn-2026aTopologyMultivariable CalculusLet and let . Then is open in the Euclidean sense if and only if for every point there exists a real number such that every point satisfying…- Let . For each index , let satisfy . The subset is called the closed box in determined by the…