Gauge Integral Structures for Stochastic Calculus and Quantum Electrodynamics. Patrick Muldowney

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x 2 right-parenthesis"/>, a loss of 11 is incurred twice, with throws of (5,6) and (6,5).

      Accordingly, let the sample space for the wager be

normal upper Omega prime equals StartSet 1 comma 2 comma 3 comma 4 comma 5 comma negative 11 comma negative 12 EndSet comma

      let the measurable sets script upper A prime consist of 2 Superscript normal upper Omega prime, the family of all subsets of normal upper Omega prime, and, for y element-of normal upper Omega prime let upper P left-parenthesis StartSet y EndSet right-parenthesis be as set out in Table 2.1; so, for upper A element-of script upper A prime, upper P left-parenthesis upper A right-parenthesis can be found by adding up the relevant probabilities in Table 2.1.

Payout Probability
1 11 slash 36
2 9 slash 36
3 7 slash 36
4 5 slash 36
5 1 slash 36
‐11 2 slash 36
‐12 1 slash 36

      Now define random variable script upper Y colon normal upper Omega prime right-arrow from bar bold upper R by the identity mapping script upper Y left-parenthesis omega prime right-parenthesis equals y for omega prime equals y element-of normal upper Omega prime. Trivially, script upper Y is left-parenthesis normal upper Omega prime comma script upper A prime comma upper P right-parenthesis‐measurable, and

normal upper E left-parenthesis script upper Y right-parenthesis equals integral Underscript normal upper Omega Superscript prime Baseline Endscripts script upper Y left-parenthesis omega Superscript prime Baseline right-parenthesis d upper P equals StartFraction 41 Over 36 EndFraction comma

      or slightly more than 1 euro.

      The random variables f left-parenthesis script upper X right-parenthesis and script upper Y are two equivalent ways of mathematically representing the wager. In [MTRV], f left-parenthesis script upper X right-parenthesis is described as a contingent form of the random variable, while script upper Y is an elementary form.

      Measurability ensures that the two forms are related. To illustrate, consider upper A prime equals StartSet 5 comma negative 11 EndSet, a subset in the range of the random variable script upper Y (or f left-parenthesis script upper X right-parenthesis. Then

f Superscript negative 1 Baseline left-parenthesis upper A prime right-parenthesis equals StartSet left-parenthesis 5 comma 5 right-parenthesis comma left-parenthesis 5 comma 6 right-parenthesis comma left-parenthesis 6 comma 5 right-parenthesis EndSet

      which is a subset upper A element-of script upper A of the sample space normal upper Omega. Both upper A and upper A prime are measurable sets (trivially), and f is a measurable function, with

StartLayout 1st Row 1st Column upper P left-parenthesis upper A prime right-parenthesis 2nd Column equals 3rd Column one thirty-sixth plus two thirty-sixths comma 2nd Row 1st Column upper P left-parenthesis f Superscript negative 1 Baseline left-parenthesis upper A prime right-parenthesis right-parenthesis 2nd Column equals 3rd Column one thirty-sixth plus one thirty-sixth plus one thirty-sixth comma 3rd Row 1st Column upper P left-parenthesis upper A prime right-parenthesis 2nd Column equals 3rd Column upper P left-parenthesis f Superscript negative 1 Baseline left-parenthesis upper A Superscript prime Baseline right-parenthesis right-parenthesis equals upper P left-parenthesis upper A right-parenthesis period EndLayout

      This kind of relationship is generally valid for contingent and elementary forms of random variables.

      Elementary statistical calculation is often learned by performing exercises such as the following.

      Example 4

      

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