  Slopes of an adelic vector bundle exhibit a behaviour akin to successive
minima. Comparisons between the two amount to a Siegel lemma. Here we use
Zhang's version for absolute minima over the algebraic numbers. We prove a
Minkowski-Hlawka theorem in this context. We also study the tensor product of
two hermitian bundles bounding both its absolute minimum and maximal slope,
thus improving an estimate of Chen. We further include similar inequalities for
exterior and symmetric powers, in terms of some lcm of multinomial
coefficients.
