Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
A Derivative Matrix is the Jacobian Matrix, and is Unique
lemmalem:differentiable-derivative-matrix-2026aAnalysisMultivariable CalculusLet and be natural numbers, let be the real numbers, and let be an open subset of Euclidean space . Let with coordinate functions as in Jacobian Matrix of a Map Between Euclidean Spaces, let , and…Differentiability at a Point for Maps Between Euclidean Spaces
definitiondef:differentiable-map-euclidean-2026aAnalysisMultivariable CalculusLet and be natural numbers, let be the real numbers, and let be an open subset of Euclidean space . Let , let , and let be a real matrix with rows and columns. Write for the…Jacobian Matrix of a Map Between Euclidean Spaces
definitiondef:jacobian-matrix-euclidean-2026aAnalysisMultivariable CalculusLet and be natural numbers, let be the real numbers, and let be an open subset of Euclidean space . Let , and for a natural number with let be the th coordinate function of , s…- Let and be natural numbers and let be the real numbers. Identify the Cartesian product of Euclidean spaces with by writing a pair , with and …
Uniqueness of the Partial Derivative on a Euclidean Open Set
lemmalem:partial-derivative-unique-euclidean-2026aMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be the real numbers, let , let , let , and let . If the partial derivative of with respec…Derivatives Along a Segment for Functions on a Euclidean Open Set
lemmalem:segment-derivative-c1-2026aMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be the real numbers, and let be the real line. Let be of class on (via clause 3 there, being real-valued), wit…- Let be natural numbers, let be an open subset of Euclidean space , let be the real numbers, and let , with coordinate functions . For a natural number , we define what it means for …
Partial Derivative on a Euclidean Open Set
definitiondef:partial-derivative-euclidean-2026aMultivariable CalculusLet be a natural number, let be an open subset of Euclidean space , let be the real numbers with absolute value , let , let , and let . We say that the…- The real numbers are a Dedekind complete ordered field, denoted , with order relation . We use the following notation on . Let . 1. (Arithmetic notation) and denote the additive and multiplicative identity elements of…
Sum, Constant Multiple, and Product Rules for One-Dimensional Derivatives
lemmalem:derivative-arithmetic-1d-2026aLet be the real numbers. Let be an interval, let , let , and let be an interior point of . Here , and denote the pointwise sum, scalar multiple and product on , given by…Derivative and Continuity of the Scaled Exponential Function
lemmalem:scaled-exponential-derivative-metric-2026aLet be the real numbers, let be the real line, let be the exponential function, let , and define by The set is an interval, an…Differentiability at an Interior Point Implies Continuity There
lemmalem:differentiable-implies-continuous-1d-2026aLet be the real numbers, and let be the real line, that is, equipped with the metric determined by the absolute value. Let be an interval, let , and let be an…Fundamental Theorem of Calculus, Part II, on a Closed Real Interval
theoremthm:ftc-part2-closed-interval-2026aLet be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…Fundamental Theorem of Calculus, Part I, on a Closed Real Interval
theoremthm:ftc-part1-closed-interval-2026aLet be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…A Continuous Function with Vanishing Derivative is Constant
corollarycor:vanishing-derivative-constant-2026aLet be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…- Let be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…
- Let be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…
- Let be real numbers with in the order of the ordered field , let be the closed interval determined by and , and let be the set of natural numbers, each being identified with its image in under the…
- Let be real numbers with in the order of the ordered field , let be the closed interval determined by and , regarded as a subset of the real line , and let the codomain carry the same metric…
Restriction Stability of Continuity and of the Derivative
lemmalem:restriction-continuity-derivative-2026aLet and be metric spaces, and let be the set of real numbers with the order of its ordered field structure; for write to mean that and . 1. (Continuity) Let , let …