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- articleMay 2011
Theorems of Erdős-Ko-Rado type in polar spaces
Journal of Combinatorial Theory Series A (JCTH), Volume 118, Issue 4Pages 1291–1312https://doi.org/10.1016/j.jcta.2011.01.003We consider Erdos-Ko-Rado sets of generators in classical finite polar spaces. These are sets of generators that all intersect non-trivially. We characterize the Erdos-Ko-Rado sets of generators of maximum size in all polar spaces, except for H(4n+1,q^2)...
- articleFebruary 2009
Tight sets, weighted m-covers, weighted m-ovoids, and minihypers
Designs, Codes and Cryptography (DCAC), Volume 50, Issue 2Pages 187–201https://doi.org/10.1007/s10623-008-9223-5Minihypers are substructures of projective spaces introduced to study linear codes meeting the Griesmer bound. Recently, many results in finite geometry were obtained by applying characterization results on minihypers (De Beule et al. 16:342---349, 2008;...
- articleSeptember 2008
On the code generated by the incidence matrix of points and hyperplanes in PG(n,q) and its dual
Designs, Codes and Cryptography (DCAC), Volume 48, Issue 3Pages 231–245https://doi.org/10.1007/s10623-008-9203-9In this paper, we study the p -ary linear code C ( PG ( n , q )), q = p h , p prime, h 1, generated by the incidence matrix of points and hyperplanes of a Desarguesian projective space PG ( n , q ), and its dual code. We link the ...
- articleJuly 2008
Partial ovoids and partial spreads in symplectic and orthogonal polar spaces
European Journal of Combinatorics (EJCM), Volume 29, Issue 5Pages 1280–1297https://doi.org/10.1016/j.ejc.2007.06.004We present improved lower bounds on the sizes of small maximal partial ovoids and small maximal partial spreads in the classical symplectic and orthogonal polar spaces, and improved upper bounds on the sizes of large maximal partial ovoids and large ...
- articleJune 2008
Partial ovoids and partial spreads in hermitian polar spaces
Designs, Codes and Cryptography (DCAC), Volume 47, Issue 1-3Pages 21–34https://doi.org/10.1007/s10623-007-9047-8We present improved lower bounds on the sizes of small maximal partial ovoids in the classical hermitian polar spaces, and improved upper bounds on the sizes of large maximal partial spreads in the classical hermitian polar spaces. Of particular ...
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- articleOctober 2007
On the smallest maximal partial ovoids and spreads of the generalized quadrangles W(q) and Q(4,q)
European Journal of Combinatorics (EJCM), Volume 28, Issue 7Pages 1934–1942https://doi.org/10.1016/j.ejc.2006.11.001We present results on the size of the smallest maximal partial ovoids and on the size of the smallest maximal partial spreads of the generalized quadrangles W(q) and Q(4,q).
- research-articleJanuary 2007
Small weight codewords in LDPC codes defined by (dual) classical generalized quadrangles
Designs, Codes and Cryptography (DCAC), Volume 42, Issue 1Pages 73–92https://doi.org/10.1007/s10623-006-9017-6AbstractWe find lower bounds on the minimum distance and characterize codewords of small weight in low-density parity check (LDPC) codes defined by (dual) classical generalized quadrangles. We analyze the geometry of the non-singular parabolic quadric in ...
- articleOctober 2006
The classification of the smallest nontrivial blocking sets in PG(n, 2)
Journal of Combinatorial Theory Series A (JCTH), Volume 113, Issue 7Pages 1543–1548https://doi.org/10.1016/j.jcta.2005.11.002We determine the smallest nontrivial blocking sets with respect to t-spaces in PG(n, 2), n ≥ 3. For t = n - 1, they are skeletons of solids in PG(n, 2); for 1 ≤ t < n - 1, they are cones with vertex an (n - t - 3)- space πn-t - 3 and base the set of ...
- articleJune 2006
Blocking All Generators of Q+(2n + 1,3), n ≥ 4
Designs, Codes and Cryptography (DCAC), Volume 39, Issue 3Pages 323–333https://doi.org/10.1007/s10623-005-5034-0We determine the smallest minimal blocking sets of Q + (2 n + 1,3), n 4.
- articleJanuary 2006
On Ovoids of Parabolic Quadrics
Designs, Codes and Cryptography (DCAC), Volume 38, Issue 1Pages 131–145https://doi.org/10.1007/s10623-005-5666-0It is known that every ovoid of the parabolic quadric Q(4, q ), q = p h , p prime, intersects every three-dimensional elliptic quadric in 1 mod p points. We present a new approach which gives us a second proof of this result and, in the case ...
- articleJuly 2005
On the Spectrum of the Sizes of Maximal Partial Line Spreads in PG(2n,q), n " 3
Designs, Codes and Cryptography (DCAC), Volume 36, Issue 1Pages 101–110https://doi.org/10.1007/s10623-004-1165-yA lot of research has been done on the spectrum of the sizes of maximal partial spreads in PG (3, q ) [P. Govaerts and L. Storme, Designs Codes and Cryptography , Vol. 28 (2003) pp. 51--63; O. Heden, Discrete Mathematics , Vol. 120 (1993) pp. 75--91;...
- articleJune 2003
Results on Maximal Partial Spreads in PG(3, p3) and on Related Minihypers
Designs, Codes and Cryptography (DCAC), Volume 29, Issue 1-3Pages 105–122https://doi.org/10.1023/A:1024196207146This article classifies all {ý( q + 1), ý; 3, q }-minihypers, ý small, q = p h 0, h ý 1, for a prime number p 0 ý 7, which arise from a maximal partial spread of deficiency ý. When q is a third power, the minihyper is the disjoint union of ...
- articleJune 2003
Some New Maximal Sets of Mutually Orthogonal Latin Squares
Designs, Codes and Cryptography (DCAC), Volume 29, Issue 1-3Pages 141–147https://doi.org/10.1023/A:1024104508963Two ways of constructing maximal sets of mutually orthogonal Latin squares are presented.
The first construction uses maximal partial spreads in PG(3, 4) \ PG(3, 2) with r lines, where r ∈ {6, 7}, to construct transversal-free translation nets of order ...
- articleMay 2003
A Griesmer bound for linear codes over finite quasi-Frobenius rings
Discrete Applied Mathematics (DAMA), Volume 128, Issue 1Pages 263–274https://doi.org/10.1016/S0166-218X(02)00450-XIn this article we give a Griesmer type bound for linear codes over finite quasi-Frobenius rings and consider linear codes over these rings meeting the bound. And we study a geometrical characterization of linear codes over finite chain rings meeting ...
- articleJanuary 2003
Maximal partial spreads of T2(O) and T3(O)
European Journal of Combinatorics (EJCM), Volume 24, Issue 1Pages 73–84https://doi.org/10.1016/S0195-6698(02)00131-2Assuming a partial spread of T2(O) or T3(O), with deficiency δ, is maximal and using results on minihypers, which are closely related to blocking sets in PG(2, q), we obtain lower bounds for δ. If q is even, using extendability of arcs in PG(2, q), we ...
- research-articleAugust 2002
On a Particular Class of Minihypers and its Applications. III. Applications
European Journal of Combinatorics (EJCM), Volume 23, Issue 6Pages 659–672https://doi.org/10.1006/eujc.2002.0599In the first two articles of this series, the structure of certain minihypers was determined. Hamada shows how these results translate into results on linear codes meeting the Griesmer bound, while Govaerts and Storme show how they can be applied to ...
- articleMay 2002
Minimal Covers of Q+(2n + 1, q) by (n − 1)-Dimensional Subspaces
Journal of Algebraic Combinatorics: An International Journal (KLU-JACO), Volume 15, Issue 3Pages 231–240https://doi.org/10.1023/A:1015060407685A i>t-cover of a quadric {\cal Q} is a set {\cal C} of i>t-dimensional subspaces contained in {\cal Q} such that every point of {\cal Q} is contained in at least one element of {\cal C} .
We consider (i>n ý 1)-covers of the hyperbolic quadric i&...
- research-articleFebruary 2002
On a Particular Class of Minihypers and Its Applications
Journal of Combinatorial Theory Series A (JCTH), Volume 97, Issue 2Pages 369–393https://doi.org/10.1006/jcta.2001.3219A particular class of minihypers was studied previously by the authors (in press, Des. Codes Cryptogr.). For q square, this paper improves the results of that work, under the assumption that no weights occur in the minihyper. Using the link between ...
- research-articleJanuary 2002
Small Minimal Blocking Sets inPG(2, q3)
European Journal of Combinatorics (EJCM), Volume 23, Issue 1Pages 83–92https://doi.org/10.1006/eujc.2001.0545We extend the results of Polverino (1999, Discrete Math., 208/209, 469 476; 2000, Des. Codes Cryptogr., 20, 319 324) on small minimal blocking sets in PG(2,p3 ), p prime, p 7, to small minimal blocking sets inPG (2, q3), q=ph, p prime, p 7, with ...
- articleNovember 2001
Linear Point Sets and Rédei Type k-blocking Sets in PG(n, q)
Journal of Algebraic Combinatorics: An International Journal (KLU-JACO), Volume 14, Issue 3Pages 221–228https://doi.org/10.1023/A:1012724219499In this paper, i>k-blocking sets in i>PG(i>n, i>q), being of Rédei type, are investigated. A standard method to construct Rédei type i>k-blocking sets in i>PG(i>n, i>q) is to construct a cone having as base a Rédei type i>ký-...