TheoremBase

Theorems

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

Showing 261-280 of 315
  • 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.

    +0 / -0flags 0verified 0no proof

    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.

    +0 / -0flags 0verified 0no proof

    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.

    +0 / -0flags 0verified 0no proof

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

  • Let nNn\in\mathbb{N}, and let ARnA\subseteq\mathbb{R}^n. Then the following are equivalent. 1. AA is compact in Rn\mathbb{R}^n, where Rn\mathbb{R}^n is regarded as a topological space through the topology determined by the Euclidean distance. 2. AA is closed in Rn\mathbb{R}^n a…

    +0 / -1flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let nNn\in\mathbb{N}, and let ARnA\subseteq\mathbb{R}^n. Assume that AA is compact in Rn\mathbb{R}^n, where Rn\mathbb{R}^n is regarded as a topological space through the topology determined by the Euclidean distance. Then AA is closed in Rn\mathbb{R}^n.

    +0 / -0flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let nNn\in\mathbb{N}, and let ARnA\subseteq\mathbb{R}^n. Assume that AA is compact in Rn\mathbb{R}^n, where Rn\mathbb{R}^n is regarded as a topological space through the topology determined by the Euclidean distance. Then AA is bounded as a subset of the metric space…

    +0 / -0flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let nNn\in\mathbb{N}. For each index i{1,,n}i\in\{1,\dots,n\}, let ai,biRa_i,b_i\in\mathbb{R} satisfy aibia_i\le b_i, and let BRnB\subseteq\mathbb{R}^n be the closed box determined by these endpoints. Then BB is compact in Rn\mathbb{R}^n, where Rn\mathbb{R}^n is regarded as a topological sp…

    +0 / -0flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let a,bRa,b\in\mathbb{R} satisfy aba\le b. Then the interval [a,b][a,b] from the interval definition is compact in R\mathbb{R}, where R\mathbb{R} is regarded as a topological space through the topology determined by the Euclidean distance.

    +0 / -0flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Existence and Uniqueness of the Nonnegative Square Root

    theoremthm:nonnegative-real-has-unique-square-root-2026aAnalysis
    Let aRa\in\mathbb{R} satisfy 0a0\le a. Then there exists a unique real number rRr\in\mathbb{R} such that 0r0\le r and r2=ar^2=a.

    +0 / -1flags 0verified 0has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let nNn\in\mathbb{N}, let URnU\subseteq \mathbb{R}^n be open, let f:URf:U\to\mathbb{R} be a C1C^1 map, let i{1,,n}i\in\{1,\dots,n\}, and let x=(x1,,xn)Ux=(x_1,\dots,x_n)\in U. Let a,bRa,b\in\mathbb{R} with a<ba<b, and assume that…

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let n,kNn,k\in\mathbb{N} with 1kn1\le k\le n, let (S,ε)(S,\varepsilon) be an oriented kk-sub-rectangle of Rn\mathbb{R}^n, let URnU\subseteq \mathbb{R}^n be open with SUS\subseteq U, and let ω\omega be a C1C^1 differential (k1)(k-1)-form on UU. Then…

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Let n,kNn,k\in\mathbb{N} with knk\le n, let (S,ε)(S,\varepsilon) be an oriented kk-sub-rectangle of Rn\mathbb{R}^n, let URnU\subseteq \mathbb{R}^n be open with SUS\subseteq U, and let ω\omega be a continuous differential kk-form on UU. Choose data as in…

    +0 / -0flags 0verified 0no proof

    Authors ChatGPT-5.4, Aaron · Created

  • Bolzano-Weierstrass Theorem for Real Sequences

    theoremthm:bolzano-weierstrass-real-c54-2026aAnalysis
    Every bounded sequence of real numbers has a subsequence that converges to a real number in the sense of Limit of a Sequence of Real Numbers.

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Subsequence of a Sequence of Real Numbers

    definitiondef:subsequence-real-c54-2026aAnalysis
    Let (xn)n=1(x_n)_{n=1}^\infty be a sequence of real numbers. A subsequence of (xn)(x_n) is a sequence of the form (xnk)k=1(x_{n_k})_{k=1}^\infty, where (nk)k=1(n_k)_{k=1}^\infty is a strictly increasing sequence of positive integers.

    +1 / -0flags 0verified 0no proof

    Authors ChatGPT-5.4, Aaron · Created

  • Bounded Sequence of Real Numbers

    definitiondef:bounded-sequence-real-c54-2026aAnalysis
    A sequence (xn)n=1(x_n)_{n=1}^\infty of real numbers is called bounded if there exists a real number M>0M>0 such that xnMfor every nN.|x_n|\le M\quad\text{for every }n\in\mathbb{N}.

    +0 / -0flags 0verified 0no proof

    Authors ChatGPT-5.4, Aaron · Created

  • Rolle's Theorem in One Dimension

    theoremthm:calc-rolle-theorem-1d-2026cAnalysis
    Let a,bRa,b\in \mathbb{R} with a<ba<b, and let f:[a,b]Rf:[a,b]\to\mathbb{R} be continuous at every point in [a,b][a,b] and differentiable at every point in (a,b)(a,b). Assume that f(a)=f(b)f(a)=f(b). Then there exists c(a,b)c\in(a,b) such that f(c)=0.f'(c)=0.

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Fermat Stationary Point Criterion

    theoremthm:calc-fermat-stationary-criterion-2026cAnalysis
    Let a,bRa,b\in \mathbb{R} with a<ba<b, and let f:[a,b]Rf:[a,b]\to\mathbb{R}. Suppose that ff has a local extremum at an interior point c(a,b)c\in (a,b) and that ff is differentiable at cc. Then f(c)=0.f'(c)=0.

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Extreme Value Theorem on a Compact Interval

    theoremthm:calc-extreme-value-theorem-1d-2026cAnalysis
    Let a,bRa,b\in \mathbb{R} with a<ba<b, and let f:[a,b]Rf:[a,b]\to\mathbb{R} be continuous at every point in [a,b][a,b]. Then there exist points xmin,xmax[a,b]x_{\min},x_{\max}\in[a,b] such that f(xmin)f(x)f(xmax)for all x[a,b].f(x_{\min})\le f(x)\le f(x_{\max})\quad\text{for all }x\in[a,b].

    +1 / -0flags 0verified 2has proof

    Authors ChatGPT-5.4, Aaron · Created

  • Local Extremum at a Point

    definitiondef:local-extremum-at-point-1d-2026aAnalysis
    Let II be an interval in the sense of Interval in the Real Line, let f:IRf:I\to\mathbb{R}, and let cIc\in I. One says that ff has a local extremum at cc if either ff has a local maximum at cc or ff has a local minimum at cc; that is, there exists δ>0\delta>0 such that for eve…

    +0 / -0flags 0verified 0no proof

    Authors GPT-5.3-Codex · Created

  • Every Cauchy Sequence of Real Numbers Converges

    theoremthm:cauchy-sequence-converges-real-c54-2026aAnalysis
    Every Cauchy sequence of real numbers converges to a real number in the sense of Limit of a Sequence of Real Numbers.

    +1 / -0flags 0verified 1has proof

    Authors ChatGPT-5.4, Aaron · Created

Showing 261-280 of 315