Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-28T20:10:44.886Z Has data issue: false hasContentIssue false

Reducible 2 – (11, 5, 4) and 3 – (12, 6, 4) designs

Published online by Cambridge University Press:  09 April 2009

D. R. Breach
Affiliation:
Department of MathematicsUniversity of CanterburyChristchurch, New Zealand
A. R. Thompson
Affiliation:
Department of MathematicsUniversity of CanterburyChristchurch, New Zealand
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

One way of constructing a 2 – (11,5,4) design is to take together all the blocks of two 2 – (11,5,2) designs having no blocks in common. We show that 58 non-isomorphic 2 – (11,5,4) designs can be so made and that through extensions by complementation these can be packaged into just 12 non-isomorphic reducible 3 – (12,6,4) designs.

MSC classification

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1985

References

[1]Breach, D. R., ‘The 2 – (9, 4, 3) and 3 – (10, 5, 3) designs,’ J. Combin. Theory Ser. A 27 (1979), 5063.CrossRefGoogle Scholar
[2]Breach, D. R., ‘Some 2 – (2n + 1, n, n – 1) designs with multiple extensions,’ Combinatorial Mathematics VI (Proceedings, Armidale, Australia) (Springer-Verlag Lecture Notes in Mathematics 748, 1979, 3240).CrossRefGoogle Scholar
[3]Cameron, P. J. and van Lint, J. H., ‘Graphs, codes and designs’ (Lond. Math. Soc. Lecture Notes Series 43, CUP, 1980).Google Scholar
[4]Dembowski, P., Finite geometries (Ergebnisse der Mathematik 44, Springer-Verlag, 1968).CrossRefGoogle Scholar
[5]Sprott, D. A., ‘Balanced incomplete block designs and tactical configurations’, Ann. of Math. Stat. 26 (1955), 752758.CrossRefGoogle Scholar
[6]Stanton, R. G., Mullin, R. C. and Bate, J. A., ‘Isomorphism classes of a set of prime BIBD parameters’, Ars Combinatoria 2 (1976), 251264.Google Scholar
[7]Thompson, A. R., Decomposable 2 – (11,5,4) and 3 – (12, 6, 4) designs, (M. Sc. thesis, University of Canterbury, 1982).Google Scholar