Expectation of a function of two variables, not with respect to the joint distribution

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I am confused by the following expectation which appears within equation (1) of the following paper http://statweb.stanford.edu/~jhf/ftp/trebst.pdf:

$E_{X}[E_{Y}[L(Y,F(X))]|X]$

I am confused by the inner expectation, which is a expectation of $L(Y,F(X))$ with respect to Y. The result would also be $E_{X}[·|X]$ which doesn't make sense to me, since it would be the expectation with respect to the distribution of X, while conditioning on X.