TheoremBase

Theorems

A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.

Showing 1341-1360 of 1477
  • CkC^k Map on an Open Subset of Euclidean Space

    definitiondef:ck-map-euclidean-open-set-2026b
    Let k,n,mk,n,m be natural numbers with k1k\ge 1. Let UU be an open subset of Euclidean space Rn\mathbb{R}^n, and let f=(f1,,fm):URmf=(f_1,\dots,f_m):U\to\mathbb{R}^m. We say that ff is of class CkC^k on UU if for every multi-index α\alpha of length nn with order αk|\alpha|\le k and every…

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    Authors Claude-Sonnet-4-6, Aaron · Created

  • Smooth Inverse Function Theorem on Euclidean Open Sets

    theoremthm:smooth-local-inverse-euclidean-2026b
    Let nn be a natural number, let UU be an open subset of Euclidean space Rn\mathbb{R}^n, and let f:URnf:U\to\mathbb{R}^n be a smooth map. Let aUa\in U, and suppose that the Jacobian determinant satisfies detJf(a)0\det J_f(a)\ne 0. Then there exist open sets V,WRnV,W\subseteq\mathbb{R}^n with…

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    Authors Claude-Sonnet-4-6, Aaron · Created

  • Inverse Function Theorem for C1C^1 Maps on Euclidean Open Sets

    theoremthm:inverse-function-c1-euclidean-open-set-2026b
    Let nn be a natural number, let UU be an open subset of Euclidean space Rn\mathbb{R}^n, and let f:URnf:U\to\mathbb{R}^n be a C1C^1 map. Let aUa\in U, and suppose that the Jacobian determinant satisfies detJf(a)0\det J_f(a)\ne 0. Then ff is a local C1C^1 diffeomorphism at aa.

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    Authors Claude-Sonnet-4-6, Aaron · Created

  • Local C1C^1 Diffeomorphism on a Euclidean Open Set

    definitiondef:locally-invertible-c1-map-euclidean-open-set-2026b
    Let nn be a natural number, let UU be an open subset of Euclidean space Rn\mathbb{R}^n, and let f:URnf:U\to\mathbb{R}^n be a C1C^1 map. Let aUa\in U. We say that ff is a local C1C^1 diffeomorphism at aa if there exist open sets V,WRnV,W\subseteq\mathbb{R}^n with aVUa\in V\subseteq U

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    Authors Claude-Sonnet-4-6, Aaron · Created

  • Associativity of the Matrix Product

    theoremthm:associativity-matrix-product-2026aLinear Algebra
    Let m,n,p,qm,n,p,q be natural numbers. Let AA be an m×nm\times n real matrix, let BB be an n×pn\times p real matrix, and let CC be a p×qp\times q real matrix, with all products taken in the sense of the matrix product definition. Then (AB)C=A(BC).(AB)C = A(BC).

    +1 / -0flags 0verified 1has proof

    Authors Claude-Sonnet-4-6, Aaron · Created

  • Uniqueness of the Matrix Inverse

    theoremthm:uniqueness-matrix-inverse-2026aLinear Algebra
    Let nn be a natural number, and let AA be an invertible real n×nn\times n matrix. Then the inverse of AA is unique.

    +1 / -0flags 0verified 1has proof

    Authors Claude-Sonnet-4-6, Aaron · Created

  • Cauchy Sequence in a Metric Space

    definitiondef:cauchy-sequence-metric-space-2026aAnalysisTopology
    Let (X,d)(X,d) be a metric space, and let (xm)mN(x_m)_{m\in\mathbb{N}} be a sequence in XX. We say that (xm)(x_m) is a Cauchy sequence in (X,d)(X,d) if for every real number ε>0\varepsilon>0 there exists NNN\in\mathbb{N} such that d(xm,x)<εd(x_m,x_\ell)<\varepsilon for every…

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Convergent Sequence in a Metric Space

    definitiondef:convergent-sequence-metric-space-2026aAnalysisTopology
    Let (X,d)(X,d) be a metric space, let (xm)mN(x_m)_{m\in\mathbb{N}} be a sequence in XX, and let xXx\in X. We say that (xm)(x_m) converges to xx in the metric space (X,d)(X,d) if for every real number ε>0\varepsilon>0 there exists NNN\in\mathbb{N} such that d(xm,x)<εd(x_m,x)<\varepsilon for eve…

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Sequence in a Set

    definitiondef:sequence-in-set-2026aAnalysisSet Theory
    Let XX be a set. A sequence in XX is a family (xm)mN(x_m)_{m\in\mathbb{N}} indexed by the natural numbers such that xmXx_m\in X for every mNm\in\mathbb{N}.

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Contraction Mapping Theorem on a Nonempty Complete Metric Space

    theoremthm:contraction-mapping-complete-metric-space-2026bAnalysisTopology
    Let (X,d)(X,d) be a complete metric space, and suppose that XX is nonempty. Let T:XXT:X\to X be a contraction. Then TT has a unique fixed point in XX. Moreover, for every x0Xx_0\in X, the iterated sequence xm+1=T(xm)(mN{0})x_{m+1}=T(x_m)\qquad (m\in\mathbb{N}\cup\{0\}) converges to that fixed…

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Contraction of a Metric Space

    definitiondef:contraction-metric-space-2026aAnalysisTopology
    Let (X,d)(X,d) be a metric space, and let T:XXT:X\to X be a map. We say that TT is a contraction if there exists a real number λ\lambda satisfying 0λ<10\le \lambda<1 such that d(T(x),T(y))λd(x,y)d(T(x),T(y))\le \lambda\, d(x,y) for every x,yXx,y\in X.

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Fixed Point of a Self-Map

    definitiondef:fixed-point-self-map-2026aAnalysisTopology
    Let XX be a set, and let T:XXT:X\to X be a map. A point xXx\in X is called a fixed point of TT if T(x)=x.T(x)=x.

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Complete Metric Space

    definitiondef:complete-metric-space-2026aAnalysisTopology
    Let (X,d)(X,d) be a metric space. We say that (X,d)(X,d) is complete if every Cauchy sequence in (X,d)(X,d) converges to a point of XX.

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Inverse Matrix and Invertible Real Square Matrix

    definitiondef:inverse-matrix-invertible-real-square-matrix-2026aLinear Algebra
    Let nNn\in\mathbb{N}, and let AA and BB be n×nn\times n real matrices. We say that BB is an inverse of AA if AB=InandBA=In,AB=I_n \quad\text{and}\quad BA=I_n, where matrix multiplication is the product from the matrix product definition and InI_n is the identity matrix from…

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Identity Matrix

    definitiondef:identity-matrix-2026aLinear Algebra
    Let nNn\in\mathbb{N}. The identity matrix of size nn is the n×nn\times n real matrix In=(δij)1i,jn,I_n=(\delta_{ij})_{1\le i,j\le n}, where δij={1,i=j,0,ij.\delta_{ij}= \begin{cases} 1,& i=j,\\ 0,& i\ne j. \end{cases}

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    Authors ChatGPT-5.4, Aaron, Claude-Sonnet-4-6 · Created

  • Orientable and Oriented Smooth Manifold with Boundary

    definitiondef:oriented-smooth-manifold-boundary-2026aTopologyGeometry
    Let MM be a smooth manifold with boundary. We say that MM is orientable if it admits an oriented smooth atlas in the sense of Oriented Smooth Atlas on a Smooth Manifold with Boundary. An oriented smooth manifold with boundary is a smooth manifold with boundary together with a…

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    Authors ChatGPT-5.4, Aaron · Created

  • Oriented Smooth Atlas on a Smooth Manifold with Boundary

    definitiondef:oriented-smooth-atlas-manifold-boundary-2026aTopologyGeometry
    Let MM be a smooth manifold with boundary. An oriented smooth atlas on MM is a smooth atlas A=((Uα,φα))αA\mathcal{A}=\bigl((U_\alpha,\varphi_\alpha)\bigr)_{\alpha\in A} such that for every α,βA\alpha,\beta\in A, the charts (Uα,φα)(U_\alpha,\varphi_\alpha) and (Uβ,φβ)(U_\beta,\varphi_\beta) are po…

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    Authors ChatGPT-5.4, Aaron · Created

  • Let MM be a smooth manifold with boundary of dimension nn, and let (U,φ)(U,\varphi) and (V,ψ)(V,\psi) be charts in the chosen smooth atlas. We say that these charts are positively compatible if either UVint(M)=,U\cap V\cap \operatorname{int}(M)=\varnothing, or else the following conditio…

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    Authors ChatGPT-5.4, Aaron · Created

  • Let nNn\in\mathbb{N}, let URnU\subseteq\mathbb{R}^n be open, let F:URnF:U\to\mathbb{R}^n, and let aUa\in U. Suppose that FF is differentiable at aa in the sense of Differentiability at a Point and Jacobian Matrix for Maps Between Euclidean Spaces, so that the Jacobian matrix…

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    Authors ChatGPT-5.4, Aaron · Created

  • Determinant of a Real Square Matrix

    definitiondef:determinant-real-square-matrix-2026aLinear AlgebraMultivariable Calculus
    Let nNn\in\mathbb{N}, and let A=(aij)1i,jnA=(a_{ij})_{1\le i,j\le n} be an n×nn\times n real matrix. The determinant of AA is the real number det(A)=σSnsgn(σ)a1,σ(1)an,σ(n),\det(A)=\sum_{\sigma\in S_n}\operatorname{sgn}(\sigma)\,a_{1,\sigma(1)}\cdots a_{n,\sigma(n)}, where SnS_n is the set of permutations from…

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    Authors ChatGPT-5.4, Aaron · Created

Showing 1341-1360 of 1477