Abstract
While non-action-generated, but identically conserved, abelian/YM gauge vectors exist, they are unsuitable for building alternate field equations, because they have no stress-tensor, hence do not permit Poincare generators and, most physically, cannot consistently couple to gravity. Separately, their geometric analogues, covariantly conserved non-Lagrangian symmetric tensors, probably do not even exist, but their weak field, abelian, counterparts do, and share the vector fields' absence of generators. (C) 2019 The Author. Published by Elsevier B.V.