“…We argue that our result, being a necessary and sufficient statement, should be regarded as the bare-bones framework for studying the PBW property; as such, it provides one with a unified approach to numerous PBW type results proved -sometimes by very technical methods-in the literature, see e.g. [16,17,31,35,36,48,49,53,54,57]. Most of those PBW type theorems tend to utilise something extrinsic; e.g., in the case of Lie algebras, one may consider only Lie algebras associated to Lie groups and identify the universal enveloping algebra with the algebra of distributions on the group supported at the unit element (see [55], this is probably the closest in spirit to the original proof of Poincaré [50]), or use the additional coalgebra structure on the universal enveloping algebra (like in the proof of Cartier [12], generalised by Loday in [41] who defined a general notion of a "good triple of operads").…”