Expected utility
= Expected utility
{title2=$\mathbb E[u(X)]$}
The <expected value> of the <utility function> applied to a random outcome, using the decision-maker's probabilities. For a finite lottery it is $\sum_xp(x)u(x)$. Under <risk neutrality> and <quasilinear utility>, auction utility is valuation minus payment upon winning and zero upon losing, so its expectation is the winning probability times the payoff conditional on winning.