Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
The Closure of a Bounded Subset of is Compact
corollarycor:closure-bounded-rn-compact-2026aAnalysisTopologyMultivariable CalculusLet be a natural number, let be the Euclidean distance on Euclidean space , which is a metric by Euclidean Distance is a Metric on , and let be the collection of subsets of that are…Compact Subset of is Bounded
theoremthm:compact-subset-rn-bounded-2026bAnalysisTopologyMultivariable CalculusLet be a natural number, let be the Euclidean distance on Euclidean space , which is a metric by Euclidean Distance is a Metric on , and let be the collection of subsets of that are…Compact Subset of is Closed
theoremthm:compact-subset-rn-closed-2026bAnalysisTopologyMultivariable CalculusLet be a natural number, let be the Euclidean distance on Euclidean space , which is a metric by Euclidean Distance is a Metric on , and let be the collection of subsets of that are…Bolzano-Weierstrass Theorem in Euclidean Space
theoremthm:bolzano-weierstrass-rn-2026aAnalysisMultivariable CalculusLet be a natural number and let be Euclidean space equipped with the Euclidean distance , which is a metric by Euclidean Distance is a Metric on . Let be bounded in , and let…Convergence in Euclidean Space is Coordinatewise Convergence
lemmalem:convergence-coordinatewise-rn-2026aAnalysisMultivariable CalculusLet be a natural number, let be the initial segment of determined by , and let be Euclidean space equipped with the Euclidean distance , which is a metric by Euclidean Distance is a Metric on . Let…Coordinate Bounds Control the Euclidean Norm
lemmalem:euclidean-norm-coordinate-bound-2026aAnalysisMultivariable CalculusLet be a natural number, let be the initial segment of determined by , and let be a point of Euclidean space . Write for the Euclidean norm, for the absolute value on the real numbers, w…- Let be a natural number, let be the Euclidean distance on Euclidean space , which is a metric by Euclidean Distance is a Metric on , and let be the collection of subsets of that are…
Elementary Properties of the Euclidean Norm on
lemmalem:euclidean-norm-properties-2026aAnalysisMultivariable CalculusLet be a natural number, let , and be points of Euclidean space , and let be a real number. The real numbers form an ordered field, with additive identity and order ; for a real number write for …Euclidean Space is a Real Vector Space
propositionprop:rn-real-vector-space-2026aLinear AlgebraMultivariable CalculusLet be a natural number. Let denote the real numbers, which form in particular a field, with additive identity , multiplicative identity , and additive inverse of an element ; for write for . Then Euclidean space…- Let be a natural number and let be a point of Euclidean space , so that each coordinate is a real number. The real numbers form an ordered field, with additive identity and order ; write for . By claim 2 of…
- Let be a natural number, and let denote the additive identity of the field of real numbers. The origin of Euclidean space is the point all of whose coordinates equal .
Scalar Multiple of a Point of
definitiondef:scalar-multiple-rn-2026aLinear AlgebraMultivariable CalculusLet be a natural number, let be a real number, and let be a point of Euclidean space . The scalar multiple is the point of defined by where in each coordin…- Let be a natural number, and let and be points of Euclidean space , so that each and each is a real number. The sum is the point of defined by where in e…
First- and Second-Order Conditions at a Local Extremum of a Function of Class
lemmalem:c2-local-extremum-conditions-2026aAnalysisLinear AlgebraMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be the set of real numbers with the operations and the order of its ordered field structure, where for we write to mean t…Differences and Constants for Functions of Class on a Euclidean Open Set
lemmalem:c2-difference-constant-2026aAnalysisMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , and let be the set of real numbers with the operations and the order of its ordered field structure, where for we write to me…Euclidean Continuity Agrees with Metric Continuity for Real-Valued Functions
lemmalem:euclidean-metric-continuity-agree-2026aAnalysisTopologyMultivariable CalculusLet be a natural number, let be a subset of Euclidean space , let be the set of real numbers with the operations and the order of its ordered field structure, where for we write to mean that…Gradient of a Real-Valued Function on a Euclidean Open Set
definitiondef:gradient-euclidean-open-set-2026aAnalysisMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be the set of real numbers, let , and let . Assume that for every the partial derivative of with respe…- Let be a natural number, let be an open subset of Euclidean space , and let . Let with , addition and scalar multiplication of points of being the coord…
A Map is Differentiable at Every Point
theoremthm:c1-implies-differentiable-2026aAnalysisMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be of class on , regarded there as a map into with and single coordinate function , and let . Th…Second-Order Taylor Expansion with Peano Remainder
theoremthm:second-order-taylor-peano-2026aAnalysisMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be of class on , and let . Let carry the operations and the order of its ordered field structure, let be t…