Given n subspaces of a finite-dimensional vector space over a fixed finite field F, we wish to find a “branch-decomposition” of these subspaces of width at most k, that is a subcubic tree T with n leaves mapped bijectively to the subspaces such that for every edge e of T , the sum of subspaces associated with leaves in one component of T −e and the sum of subspaces associated with leaves in the...
