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On isometric full embeddings of symplectic dual polar spaces into Hermitian dual polar spaces

โœ Scribed by Bart De Bruyn


Publisher
Elsevier Science
Year
2009
Tongue
English
Weight
192 KB
Volume
430
Category
Article
ISSN
0024-3795

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โœฆ Synopsis


Let n 2, let K, K be fields such that K is a quadratic Galoisextension of K and let ฮธ denote the unique nontrivial element in Gal(K /K). Suppose the symplectic dual polar space DW (2n -1, K) is fully and isometrically embedded into the Hermitian dual polar space DH(2n -1, K , ฮธ). We prove that the projective embed- ding of DW (2n -1, K) induced by the Grassmann-embedding of DH(2n -1, K , ฮธ) is isomorphic to the Grassmann-embedding of DW (2n -1, K). We also prove that if n is even, then the set of points of DH(2n -1, K , ฮธ) at distance at most n 2 -1 from DW (2n -1, K) is a hyperplane of DH(2n -1, K , ฮธ) which arises from the Grassmann-embedding of DH(2n -1, K , ฮธ).


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