# Probability measure

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probability distribution, probability

A real non-negative function on a class of subsets (events) of a non-empty set (the space of elementary events) forming a -field (i.e. a set closed with respect to countable set-theoretic operations) such that if for ( -additivity).

## Contents

### Examples of probability measures.

1) ; is the class of all subsets of ; (this probability measure corresponds to a random experiment consisting in throwing a symmetrical coin; if heads correspond to 1 while tails correspond to 2, the probability of throwing heads (tails) is 1/2);

2) ; is the class of all subsets of ; where (the Poisson distribution);

3) ; is the class of Borel subsets of ; (the normal distribution);

4) is the space of continuous real functions on that vanish at the point zero; is the class of Borel subsets with respect to the topology of uniform convergence; is the measure which is uniquely defined by the formula   where is an arbitrary natural number and (the Wiener measure).

How to Cite This Entry:
Probability measure. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Probability_measure&oldid=11376
This article was adapted from an original article by V.V. Sazonov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article