Abstract
Let P be a finite classical polar spaceof rank r, with r ≥ 2. A partial m-system M of P, with 0 ≤ m ≤ r - 1,is any set π1,π2,...,πk of k≠ 0 totally singular m-spacesof P such that no maximal totally singular spacecontaining πi has a point in common with (π1∪π2∪... ∪ π_k)-πi, i=1,2,\dots,k. In aprevious paper an upper bound δ for |M|was obtained (Theorem 1). If |M|=δ, then Mis called an m-system of P. For m=0the m-systems are the ovoids of P;for m=r-1 the m-systems are the spreadsof P. In this paper we improve in many cases theupper bound for the number of elements of a partial m-system,thus proving the nonexistence of several classes of m-systems.
Similar content being viewed by others
References
E. F. Assmus, Jr. and J. D. Key, Designs and Their Codes, Cambridge University Press, Cambridge (1992).
A. Blokhuis and G. E. Moorhouse, Some p-ranks related to orthogonal spaces, J. Alg. Combin., 14 (1995), 295–316.
W. Burau, Mehrdimensionale Projektive und Höhere Geometrie, VEB Deutscher Verlag derWissenschaften, Berlin (1961).
J. W. P. Hirschfeld and J. A. Thas, General Galois Geometries, Oxford University Press, Oxford (1991).
N. Jacobson, Basic Algebra I. W. H. Freeman and Comp., San Francisco (1974).
G. E. Moorhouse, A note on p-ranks related to Hermitian surfaces. J. Stat. Planning Inf., Submitted (1994).
E. E. Shult and J. A. Thas, m-systems of polar spaces. J. Combin. Theory Ser. A. 168 (1994), 184–204.
J. A. Thas, Projective geometryover a finite field, Chapter 7 of Handbook of Incidence Geometry (F. Buekenhout, ed.), Elsevier, Amsterdam (1995).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Shult, E.E., Thas, J.A. m-Systems and Partial m-Systemsof Polar Spaces. Designs, Codes and Cryptography 8, 229–238 (1996). https://doi.org/10.1023/A:1018053530453
Issue Date:
DOI: https://doi.org/10.1023/A:1018053530453