David Quintero on Nostr: nprofile1q…8cnse nprofile1q…r59k6 I've found this in MTW's "Gravitation". They ...nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqdpcm4gtfv09u6rgv3v0kfp0pwq02mfcax7qljll2373npf90g74qn8cnse (nprofile…cnse) nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqc9m22hkc5h6zgrwkz48crhcpw6vch2rf6j97746ugl3neys86jeqcr59k6 (nprofile…59k6) I've found this in MTW's "Gravitation". They cite Cartan, and give an explanation (for physicists):