Classical microcanonical ensemble

context	$\Delta \in \mathbb R_+$
definiendum	$\langle \mathcal M, H,{\hat\rho}\rangle \in \mathrm{it}$
postulate	$\langle \mathcal M, H,{\hat\rho}\rangle$ … classical statistical ensemble
postulate	$\hat\rho: \mathbb R_+\to(\Gamma_{\mathcal M} \to\mathbb R_+)$
postulate	$\hat\rho(E;{\bf q},{\bf p}):=\begin{cases} 1 & \mathrm{if}\ E\le H({\bf q},{\bf p})\le E+\Delta \\\\ 0 & \mathrm{else} \end{cases}$