Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
An Operator with an Orthonormal Eigenbasis is Positive Semi-Definite Exactly When its Eigenvalues are Nonnegative
lemmalem:positive-semidefinite-iff-nonnegative-eigenvalues-2026aAnalysisLinear AlgebraLet together with be a complex inner product space with zero vector . Let be a natural number, let be the initial segment determined by , and let be an -tuple in that is an orthonormal basis of , with comp…Second-Order Expansion of the N-Agent Cost about a Stationary Mean-Field Trajectory
theoremthm:n-agent-cost-expansion-2026cProbabilityAdopt the setting of the fluctuation processes of the controlled -agent dynamics: a transition-rate family on states with control set , a nonempty subset of Euclidean space , and rate bound , an observation-rate family ,…Operators Diagonal in an Orthonormal Basis
lemmalem:orthonormal-diagonal-operator-2026aAnalysisLinear AlgebraLet together with be a complex inner product space. Let be a natural number, let be the initial segment determined by , and let be an -tuple in that is an orthonormal basis of , with components . Let…A Priori Second-Moment Bound for the State Fluctuation Process
lemmalem:fluctuation-state-moment-bound-2026bProbabilityAdopt the setting of the fluctuation processes of the controlled -agent dynamics: a transition-rate family on states with control set , a nonempty subset of Euclidean space , and rate bound , an observation-rate family ,…The Eigenvalues of an Operator with an Orthonormal Eigenbasis
lemmalem:eigenvalues-orthonormal-eigenbasis-2026aAnalysisLinear AlgebraLet together with be a complex inner product space with zero vector . Let be a natural number, let be the initial segment determined by , and let be an -tuple in that is an orthonormal basis of , with comp…Action of an Operator with an Orthonormal Eigenbasis
lemmalem:orthonormal-eigenbasis-action-2026aAnalysisLinear AlgebraLet together with be a complex inner product space with zero vector . Let be a natural number, let be the initial segment determined by , and let be an -tuple in that is an orthonormal basis of , with comp…- Let , , , with rate bound , with derivative bound , , with second-derivative bound , , and be as in the definition of a stationary mean-field triple, let be the…
- Let be a complex vector space, let be a linear operator on , and let be a complex number. The number is an eigenvalue of if there exists a vector that is an eigenvector of with eigenvalue .
- Let and be natural numbers with and . Let be a nonempty subset of Euclidean space , let be a transition-rate family on states with control set and rate bound , let be a…
Joint Measurability of the State and Control of the Controlled N-Agent Dynamics
lemmalem:n-agent-joint-measurability-2026bProbabilityAdopt the setting of the controlled -agent dynamics with agents, states, observation channels, and control dimension , and let be a nonempty subset of Euclidean space : a transition-rate family with control set…Regularity and Derivative Bounds of the Extended Aggregate State Drift
lemmalem:extended-drift-regularity-2026bProbabilityLet and be natural numbers with and , let be a nonempty subset of Euclidean space , let be a transition-rate family on states with control set and rate bound , let be a…Integration by Parts for Indefinite Lebesgue Integrals on a Compact Interval
lemmalem:lebesgue-integration-by-parts-2026bAnalysisLet be a real number, and let be measurable with respect to the trace Borel -algebra on and Lebesgue integrable over . Let and be real numbers and define…Multivariate Taylor Expansion with Uniform Second-Order Remainder
lemmalem:taylor-second-order-uniform-2026cAnalysisAlong a segment in an open subset of ℝⁿ, entrywise bounds on the first or second partial derivatives of a function give a Lipschitz bound, a first-order remainder bound and a second-order remainder bound.Continuous Real-Valued Functions on a Compact Interval are Bounded
lemmalem:continuous-compact-interval-bounded-2026bAnalysisLet and be real numbers with , and let be continuous on , the interval being regarded as a subset of the real line with the absolute value metric and carrying the same metric. Then there is a real number such that…Twice Continuously Differentiable Extension of Population Cost Data
definitiondef:c2-population-cost-extension-2026cProbabilityLet and be natural numbers with and , let be population cost data on states with control dimension , let be the probability simplex, and let be a real number. Points of ar…Twice Continuously Differentiable Extension of a Transition-Rate Family
definitiondef:c2-transition-rate-extension-2026cProbabilityLet and be natural numbers with and , let be a nonempty subset of Euclidean space , let be a transition-rate family on states with control set and rate bound , let be the…Fluctuation Processes of the Controlled N-Agent Dynamics
definitiondef:n-agent-fluctuation-processes-2026cProbabilityAdopt the setting of the controlled -agent dynamics with agents, states, observation channels, and control dimension , and let be a nonempty subset of Euclidean space : a transition-rate family on states with contr…- Let and be natural numbers with and , let be a nonempty subset of Euclidean space , let be a nonnegative real number, let be a transition-rate family on states with control set and rate bound , le…
- Let and be natural numbers with and , let be a nonempty subset of Euclidean space , let be a nonnegative real number, let be a transition-rate family on states with control set and rate bound , le…
Spectral Theorem for a Self-Adjoint Operator in Finite Dimensions
theoremthm:spectral-theorem-self-adjoint-2026aAnalysisLinear AlgebraLet together with be a complex inner product space with zero vector , and suppose that is finite-dimensional and ; write for its dimension and let be the initial segment determined by . Let be a…