Kartik Prabhu replied to a post on Twitter with That is not some special property of the BMS group. It also happens with Lorentz in the Poincare group and for rotations within the Euclidean group. The semi-direct product is not some mysterious property of BMS. Send me the link to your response (Learn more) Send Replies Leo C. Stein 🦁 replied on Twitter with I’m aware. Likes Will M Farr on Twitter