Important stuff not done in the lecture. Moments: $\bE[X^k]$ \begin{lemma} Let $X, Y : \Omega \to [a,b]$ If $\bE[X^k] = \bE[Y^k]$, for every $k \in \N_0$ then $X = Y$. \end{lemma} \begin{proof} We have $\bE[p(X)] = \bE[p(Y)]$ for every polynomial $p$. Approximate $e^{\i t X}$ with polynomials and use Fourier transforms. \end{proof} Laplace transforms