Skip to main content
Top
Published in: Designs, Codes and Cryptography 2/2014

01-08-2014

Covering of subspaces by subspaces

Author: Tuvi Etzion

Published in: Designs, Codes and Cryptography | Issue 2/2014

Login to get access

Activate our intelligent search to find suitable subject content or patents.

search-config
loading …

Abstract

Lower and upper bounds on the size of a covering of subspaces in the Grassmann graph \(\mathcal{G }_q(n,r)\) by subspaces from the Grassmann graph \(\mathcal{G }_q(n,k)\), \(k \ge r\), are discussed. The problem is of interest from four points of view: coding theory, combinatorial designs, \(q\)-analogs, and projective geometry. In particular we examine coverings based on lifted maximum rank distance codes, combined with spreads and a recursive construction. New constructions are given for \(q=2\) with \(r=2\) or \(r=3\). We discuss the density for some of these coverings. Tables for the best known coverings, for \(q=2\) and \(5 \le n \le 10\), are presented. We present some questions concerning possible constructions of new coverings of smaller size.
Literature
1.
go back to reference Abel R.J.R., Furino S.C.: Kirkman triple systems. In: Colburn C.J., Dinitz J.H. (eds.) The CRC Handbook of Combinatorial Designs, pp. 88–89. CRC Press, Boca Raton (1996). Abel R.J.R., Furino S.C.: Kirkman triple systems. In: Colburn C.J., Dinitz J.H. (eds.) The CRC Handbook of Combinatorial Designs, pp. 88–89. CRC Press, Boca Raton (1996).
2.
go back to reference Ahlswede R., Aydinian H.K., Khachatrian L.H.: On perfect codes and related concepts. Des. Codes Cryptogr. 22, 221–237 (2001). Ahlswede R., Aydinian H.K., Khachatrian L.H.: On perfect codes and related concepts. Des. Codes Cryptogr. 22, 221–237 (2001).
3.
go back to reference Beutelspacher A.: On parallelisms in finite projective spaces. Geom. Dedic. 3, 35–45 (1974). Beutelspacher A.: On parallelisms in finite projective spaces. Geom. Dedic. 3, 35–45 (1974).
4.
go back to reference Beutelspacher A.: On \(t\)-covers in finite projective spaces. Geom. Dedic. 12, 10–16 (1979). Beutelspacher A.: On \(t\)-covers in finite projective spaces. Geom. Dedic. 12, 10–16 (1979).
5.
go back to reference Beutelspacher A., Ueberberg J.: A characteristic property of geometric \(t\)-spreads in finite projective spaces. Eur. J. Comb. 12, 277–281 (1991). Beutelspacher A., Ueberberg J.: A characteristic property of geometric \(t\)-spreads in finite projective spaces. Eur. J. Comb. 12, 277–281 (1991).
6.
go back to reference Blackburn S., Etzion T.: The asymptotic behavior of Grassmannian codes. IEEE Trans. Inf. Theory 58, 6605–6609 (2012). Blackburn S., Etzion T.: The asymptotic behavior of Grassmannian codes. IEEE Trans. Inf. Theory 58, 6605–6609 (2012).
7.
go back to reference Bose R.C., Burton R.C.: A characterization of flat spaces in finite geometry and the uniqueness of the Hamming and the MacDonald codes. J. Comb. Theory 1, 96–104 (1966). Bose R.C., Burton R.C.: A characterization of flat spaces in finite geometry and the uniqueness of the Hamming and the MacDonald codes. J. Comb. Theory 1, 96–104 (1966).
8.
go back to reference Braun M., Kerber A., Laue R.: Systematic construction of \(q\)-analogs of \(t-(v, k,\lambda )\)-designs. Des. Codes. Cryptogr. 34, 55–70 (2005). Braun M., Kerber A., Laue R.: Systematic construction of \(q\)-analogs of \(t-(v, k,\lambda )\)-designs. Des. Codes. Cryptogr. 34, 55–70 (2005).
9.
go back to reference de Caen D.: Extension of a theorem of Moon and Moser on complete subgraphs. Ars Comb. 16, 5–10 (1983). de Caen D.: Extension of a theorem of Moon and Moser on complete subgraphs. Ars Comb. 16, 5–10 (1983).
10.
go back to reference de Caen D.: The current status of Turán’s problem on hypergraphs. In: Frankl P., Füredi Z., Katona G., and Miklós D. (eds.) Extremal Problems for Finite Sets, pp. 187–197. János Bolyai mathematical society, Budapest (1991). de Caen D.: The current status of Turán’s problem on hypergraphs. In: Frankl P., Füredi Z., Katona G., and Miklós D. (eds.) Extremal Problems for Finite Sets, pp. 187–197. János Bolyai mathematical society, Budapest (1991).
11.
go back to reference Delsarte P.: Bilinear forms over a finite field, with applications to coding theory. J. Comb. Theory Ser. A. 25, 226–241 (1978). Delsarte P.: Bilinear forms over a finite field, with applications to coding theory. J. Comb. Theory Ser. A. 25, 226–241 (1978).
12.
go back to reference Eisfeld J., Metsch K.: Blocking \(s\)-dimensional subspaces by lines in PG(\(2s, q\)). Combinatorica 17, 151–162 (1997). Eisfeld J., Metsch K.: Blocking \(s\)-dimensional subspaces by lines in PG(\(2s, q\)). Combinatorica 17, 151–162 (1997).
13.
go back to reference Etzion T., Silberstein N.: Error-correcting codes in projective space via rank-metric codes and Ferrers diagrams. IEEE Trans. Inf. Theory 55, 2909–2919 (2009). Etzion T., Silberstein N.: Error-correcting codes in projective space via rank-metric codes and Ferrers diagrams. IEEE Trans. Inf. Theory 55, 2909–2919 (2009).
14.
go back to reference Etzion T., Silberstein N.: Codes, designs related to lifted MRD codes. IEEE Trans. Inf. Theory to appear; also in arxiv.org/abs/1102.2593 Etzion T., Silberstein N.: Codes, designs related to lifted MRD codes. IEEE Trans. Inf. Theory to appear; also in arxiv.org/abs/1102.2593
15.
go back to reference Etzion T., Vardy A.: Error-correcting codes in projective spaces. IEEE Trans. Inf. Theory 57, 1165–1173 (2011). Etzion T., Vardy A.: Error-correcting codes in projective spaces. IEEE Trans. Inf. Theory 57, 1165–1173 (2011).
16.
go back to reference Etzion T., Vardy A.: On \(q\)-analogs for Steiner systems and covering designs. Adv. Math. Commun. 5, 161–176 (2011). Etzion T., Vardy A.: On \(q\)-analogs for Steiner systems and covering designs. Adv. Math. Commun. 5, 161–176 (2011).
17.
go back to reference Gabidulin E.M.: Theory of codes with maximum rank distance. Probl. Inf. Transm. 21, 1–12 (1985). Gabidulin E.M.: Theory of codes with maximum rank distance. Probl. Inf. Transm. 21, 1–12 (1985).
18.
go back to reference Itoh T.: A new family of 2-designs over GF(\(q\)) admitting SL\(_m(q^\ell \)). Geom. Dedic. 69, 261–286 (1998). Itoh T.: A new family of 2-designs over GF(\(q\)) admitting SL\(_m(q^\ell \)). Geom. Dedic. 69, 261–286 (1998).
19.
go back to reference Koetter R., Kschischang F.R.: Coding for errors and erasures in random network coding. IEEE Trans. Inf. Theory 54, 3579–3591 (2008). Koetter R., Kschischang F.R.: Coding for errors and erasures in random network coding. IEEE Trans. Inf. Theory 54, 3579–3591 (2008).
20.
go back to reference Kohnert A., Kurz S.: Construction of large constant dimension codes with a prescribed minimum distance. Lect. Notes Comput. Sci. 5393, 31–42 (2008). Kohnert A., Kurz S.: Construction of large constant dimension codes with a prescribed minimum distance. Lect. Notes Comput. Sci. 5393, 31–42 (2008).
21.
go back to reference Lunardon G.: Normal spreads. Geom. Dedic. 75, 245–261 (1999). Lunardon G.: Normal spreads. Geom. Dedic. 75, 245–261 (1999).
22.
go back to reference Metsch K.: Blocking sets in projective spaces and polar spaces. J. Geom. 76, 216–232 (2003). Metsch K.: Blocking sets in projective spaces and polar spaces. J. Geom. 76, 216–232 (2003).
23.
go back to reference Miyakawa M., Munemasa A., Yoshiara S.: On a class of small 2-designs over GF(\(q\)). J. Comb. Des. 3, 61–77 (1995). Miyakawa M., Munemasa A., Yoshiara S.: On a class of small 2-designs over GF(\(q\)). J. Comb. Des. 3, 61–77 (1995).
24.
go back to reference Roth R.M.: Maximum-rank array codes and their application to crisscross error correction. IEEE Trans. Inf. Theory 37, 328–336 (1991). Roth R.M.: Maximum-rank array codes and their application to crisscross error correction. IEEE Trans. Inf. Theory 37, 328–336 (1991).
25.
go back to reference Schönheim J.: On coverings. Pac. J. Math. 14, 1405–1411 (1964). Schönheim J.: On coverings. Pac. J. Math. 14, 1405–1411 (1964).
26.
go back to reference Schwartz M., Etzion T.: Codes and anticodes in the Grassman graph. J. Comb. Theory Ser. A 97, 27–42 (2002). Schwartz M., Etzion T.: Codes and anticodes in the Grassman graph. J. Comb. Theory Ser. A 97, 27–42 (2002).
27.
go back to reference Silva D., Kschischang F.R., Koetter R.: A rank-metric approach to error control in random network coding. IEEE Trans. Inf. Theory. 54, 3951–3967 (2008). Silva D., Kschischang F.R., Koetter R.: A rank-metric approach to error control in random network coding. IEEE Trans. Inf. Theory. 54, 3951–3967 (2008).
28.
go back to reference Suzuki H.: 2-designs over GF(\(2^m\)). Gr. Comb.6, 293–296 (1990). Suzuki H.: 2-designs over GF(\(2^m\)). Gr. Comb.6, 293–296 (1990).
29.
go back to reference Suzuki H.: 2-designs over GF(\(q\)). Gr. Comb. 8, 381–389 (1992). Suzuki H.: 2-designs over GF(\(q\)). Gr. Comb. 8, 381–389 (1992).
30.
go back to reference Thomas S.: Designs over finite fields. Geom. Dedic. 21, 237–242 (1987). Thomas S.: Designs over finite fields. Geom. Dedic. 21, 237–242 (1987).
31.
go back to reference Thomas S.: Designs and partial geometries over finite fields. Geom. Dedic. 63, 247–253 (1996). Thomas S.: Designs and partial geometries over finite fields. Geom. Dedic. 63, 247–253 (1996).
32.
go back to reference van Lint J.H., Wilson R.M.: A Course in Combinatorics. Cambridge University Press, New York (1992). van Lint J.H., Wilson R.M.: A Course in Combinatorics. Cambridge University Press, New York (1992).
33.
go back to reference Zaicev G.V., Zinoviev V.A., Semakov N.V.: Interrelations of preparata and Hamming codes and extension of Hamming codes to new double error-correcting codes. In: Proceedings of 2nd International Symposium Information Theory, pp. 257–263. Budapest (1971). Zaicev G.V., Zinoviev V.A., Semakov N.V.: Interrelations of preparata and Hamming codes and extension of Hamming codes to new double error-correcting codes. In: Proceedings of 2nd International Symposium Information Theory, pp. 257–263. Budapest (1971).
Metadata
Title
Covering of subspaces by subspaces
Author
Tuvi Etzion
Publication date
01-08-2014
Publisher
Springer US
Published in
Designs, Codes and Cryptography / Issue 2/2014
Print ISSN: 0925-1022
Electronic ISSN: 1573-7586
DOI
https://doi.org/10.1007/s10623-012-9766-3

Other articles of this Issue 2/2014

Designs, Codes and Cryptography 2/2014 Go to the issue

Premium Partner