The hyperplanes of arising from embedding

We determine all hyperplanes of the dual polar space D Q − ( 7 , K ) which arise from embedding. This extends one of the results of [B. De Bruyn. The hyperplanes of D Q ( 2 n , K ) and D Q − ( 2 n + 1 , q ) which arise from their spin-embeddings, J. Combin. Theory Ser. A 114 (2007), 681–691] to the infinite case.