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I have a simple question: what is the difference, if at all, between

$ P(A|X,Y) $

and

$ P(A|X\And Y) $

and what form would these two take if represented using bayes theorem? thanks

1 Answers 1

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If $A$, $X$ and $Y$ are events then I would read them as being the same.

You have $\Pr(A|X,Y) = \dfrac{\Pr(X,Y|A)\Pr(A)}{\Pr(X,Y)}$ (assuming the denominator is positive) which you can also write many different ways, such as $\Pr(A|X,Y) = \dfrac{\Pr(X|A,Y)\Pr(Y|A)\Pr(A)}{\Pr(X|Y)\Pr(Y)}.$