Appendix 1—table 2. Compartments’ description.

${\varphi }_i$	Fraction of a given species i (cis, medial or trans) in a compartment
$\overrightarrow{C}$	Composition of a compartment, whose components are the fractions ${\varphi }_i$
$n$	Size of a compartment, (i.e. number of membrane patches in the compartment)
$n_i$	Number of membrane patches of the $i$ identity, in a compartment
$n_{\mathrm{id}}$	Number of different identities (from 1 to 3) in a single a compartment
$n_{\mathrm{v}}$	Number of vesicles surrounding a compartment that share its composition
$P$	Purity of a compartment
$J_{\mathrm{b},\text{𝑖}}$	Budding flux of vesicles decorated by the identity $i$, from a compartment