Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
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-2026bProbabilityThroughout, a real-valued function on a subinterval of the real numbers is called continuous on when it is continuous relative to , both and the codomain carrying the metric of the real line. Let be a…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-2026bProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , let be the real numbers, let be real, and let denote…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…The Elementary Stochastic Integral Process is a Square-Integrable Martingale
lemmalem:elementary-stochastic-integral-martingale-2026aProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to , let be real, and let be a simple adapted process on . For , the…Linearity, Mean Zero, and Isometry of the Elementary Stochastic Integral
lemmalem:elementary-stochastic-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 simple adapted processes on , and let be r…Elementary Stochastic Integral of a Simple Adapted Process
definitiondef:elementary-stochastic-integral-2026aProbabilityLet be a filtered probability space, let be an It^{o} integrator of intensity type with respect to (the intensity plays no role in this definition), let be real, and let be a…- Let be a filtered probability space and let be a real number. A simple adapted process on is a family of random variables on for which there exist a natural number…
- Let be a filtered probability space and let denote Lebesgue measure on the real line. An It^{o} integrator of intensity type with respect to is a pair consisting of a…
Mean-Square Limits of Gaussian Random Vectors are Gaussian
theoremthm:gaussian-vector-mean-square-limit-2026aProbabilityLet be a probability space and let be a natural number. For each let be a Gaussian random vector on , and let be square-integrable random variables such that…Triangular Orthonormalization of a Positive Definite Gram Matrix
lemmalem:triangular-orthonormalization-gram-2026aLinear AlgebraLet be a natural number and let be a real matrix that is symmetric, with the transpose, and positive definite: for every nonzero (Euclidean space), the dot product with the matrix-vector product satisfies . C…Independence is Preserved by Limits in Probability
lemmalem:independence-limits-in-probability-2026aProbabilityLet be a probability space, let be a natural number, and for each let be independent random variables on it. Let be random variables such that for each the sequence…Mean-Square Limits of Gaussian Random Variables are Gaussian
lemmalem:gaussian-mean-square-limit-2026aProbabilityLet be a probability space, let be a sequence of Gaussian random variables on it, and let be a square-integrable random variable such that the mean-square distance satisfies as . Then…Uniform Mean-Square Continuity on a Compact Interval
lemmalem:uniform-mean-square-continuity-2026bProbabilityLet be a probability space, let be the real numbers, let be real numbers, and let be a family of square-integrable random variables that is mean-square continuous on the closed interval . Then…Mean-Square Continuous Family of Random Variables
definitiondef:mean-square-continuous-process-2026aProbabilityLet be a probability space, let be a nonempty set of real numbers, and let be a family of square-integrable random variables on , with the mean-square norm of that definition. The famil…Increments Are Independent of the Natural Filtration Past
lemmalem:increments-independent-natural-filtration-2026aProbabilityLet be a probability space and let be a stochastic process on it with independent increments. Suppose there is a real number such that almost surely. Let be the natural filtration of . Then f…