<<< native [ EUnder False (EIdentifier "B") (EIdentifier "underscript") , ESymbol Rel "=" , EUnder False (EGrouped [ EPhantom (ENumber "1") , EIdentifier "B" , EPhantom (ENumber "1") ]) (EIdentifier "underscript") ] >>> eqn B from underscript = {hphantom 1 B hphantom 1} from underscript