This is actually the precise definition of conditional probability derived from Kolmogorov's measure theoretical construction of probability. It's easily the mo

This is actually the precise definition of conditional probability derived from Kolmogorov's measure theoretical construction of probability. It's easily the most popular construction of probability. http://en.wikipedia.org/wiki/Probability_space http://en.wikipedia.org/wiki/Probability_space http://en.wikipedia.org/wiki/Probability_axioms http://en.wikipedia.org/wiki/Probability_axioms