Adhesive polymatroids were defined by F. Matúš motivated by entropy functions. Two polymatroids are adhesive if they can be glued together along their joint part in a modular way; and are one-adhesive, if one of them has a single point outside their intersection. It is shown that two polymatroids are one-adhesive if and only if two closely related polymatroids have joint extension. Using this result, adhesive polymatroid pairs on a five-element set are characterized.
polymatroid, entropy function, amalgam, adhesive polymatroid, polyhedral cone
05B35, 94A15, 52B12