Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
Linear-Gaussian State-Observation Model
definitiondef:linear-gaussian-state-observation-model-2026aProbabilityLet be a probability space, let be real, let be natural numbers, and let be an -dimensional Brownian motion on . Let (), (), (…Gaussian Structure and Moment Equations for Linear Stochastic Differential Equations
lemmalem:linear-sde-gaussian-covariance-2026aProbabilityLet be a linear stochastic differential equation with additive Wiener noise on whose forcing family has every member equal to the zero tuple, with dimensions , and let be any mean-square solution of it, with versions fixed (any two mean-…Second-Moment Evolution for Processes of Integral Form
lemmalem:second-moment-evolution-2026bProbabilityLet be a probability space, let be real numbers with , let be a natural number, and let be an -dimensional Brownian motion. Let be square-integrable random variables, let an…Existence, Uniqueness, and Variation of Constants for Linear Stochastic Differential Equations
theoremthm:linear-sde-variation-of-constants-2026aProbabilityLet be a linear stochastic differential equation with additive Wiener noise on , with dimensions as there, and let and be the fundamental solution of on and its inverse from…Mean-Square Solution of a Linear Stochastic Differential Equation with Additive Wiener Noise
definitiondef:linear-sde-mean-square-solution-2026aProbabilityLet be a probability space, let be real, let be natural numbers, and let be an -dimensional Brownian motion on . Let assign to each a real matrix and…Wiener Integrals Against a Vector Brownian Motion are Jointly Gaussian
theoremthm:vector-wiener-integral-gaussian-2026aProbabilityLet be a probability space, let be a natural number, and let be an -dimensional Brownian motion on . For each component index , each real , and each continuous , let…Independent Jointly Gaussian Families are Jointly Gaussian
lemmalem:independent-gaussian-families-jointly-gaussian-2026aProbabilityLet be a probability space, let be a natural number, and for each let be a nonempty set and let be a jointly Gaussian family of random variables on . Suppose that the…- Let be a probability space and let be a natural number. An -dimensional Brownian motion on is a family of stochastic processes on such that:…
Integration by Parts for Wiener Integrals and Mean-Square Riemann Integrals
lemmalem:stochastic-integration-by-parts-2026aProbabilityLet be a probability space, let be real, and let be continuous functions such that, with the Riemann integral (existing by Continuous Functions on a Closed Interval are Riemann Integrable),…Mean-Square Riemann Integrals of a Jointly Gaussian Family are Jointly Gaussian
lemmalem:mean-square-riemann-integral-gaussian-2026aProbabilityLet be a probability space, let be real numbers, let be a set (possibly empty), and let be a family of random variables on . Let be a mean-square continuous family of square-integrable…Basic Properties of the Mean-Square Riemann Integral
lemmalem:mean-square-riemann-integral-properties-2026aProbabilityLet be a probability space, let be real numbers, and let and be mean-square continuous families of square-integrable random variables on , with and…Existence and Uniqueness of the Mean-Square Riemann Integral for Mean-Square Continuous Families
lemmalem:mean-square-riemann-integral-existence-2026aProbabilityLet be a probability space and let be real numbers. 1. (Uniqueness) Let be any family of square-integrable random variables on . If and are both mean-square Riemann integrals of…Mean-Square Riemann Integral of a Family of Random Variables
definitiondef:mean-square-riemann-integral-2026aProbabilityLet be a probability space, let be real numbers, and let be a family of square-integrable random variables on , with the mean-square norm of that definition. Let…Wiener Integrals of Continuous Functions are Jointly Gaussian
theoremthm:wiener-integral-gaussian-2026aProbabilityLet be a standard Brownian motion on a probability space , with its natural filtration , regarded as the It^{o} integrator of Brownian Motion is an Ito Integrator with Unit Intensity. For a real …The Compensated Poisson Process is an Ito Integrator with Its Intensity
lemmalem:compensated-poisson-ito-integrator-2026aProbabilityLet be an intensity function with mean function in the sense of Stochastic Process, Independent Increments, and Inhomogeneous Poisson Process (intensity functions are nonnegative, so may be regard…Brownian Motion is an Ito Integrator with Unit Intensity
lemmalem:brownian-motion-ito-integrator-2026aProbabilityLet be a standard Brownian motion on a probability space , and let be its natural filtration. Then is a square-integrable martingale with respect to , and the pair …Adapted Mean-Square Continuous Processes are Ito Integrable
lemmalem:mean-square-continuous-ito-integrable-2026aProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , let be real, and let denote Lebesgue measure. Let be a fa…Properties of the Ito Integral: Linearity, Isometry, Martingale Property, and Mean-Square Continuity
theoremthm:ito-integral-properties-2026aProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , let be real, let and be It^{o} integrable…- Let be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , and let be real. A family of square-integrable random variables…
Existence and Uniqueness of the Mean-Square Extension of the Elementary Stochastic Integral
theoremthm:ito-integral-existence-2026aProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , let be real, and let denote Lebesgue measure. Let be a…