Abstract
Since the advent of design theory that began with constructive results of R.C. Bose and M. Hall, symmetric designs have occupied a very special status. This is due to several reasons, two most important of which are the structural symmetry and the difficulty in constructions of these designs (compared to other classes of designs). The initial part of this exposition will concentrate on new results on symmetric designs. Quasi-symmetric designs are closely related to symmetric designs. These are designs that have (at the most) two block intersection numbers. One can associate a block graph with a quasi-symmetric design and in many cases of interest, this also turns out to be a graph with special properties, and is called a strongly regular graph. One trivial way of constructing quasi-symmetric designs is to take multiple copies of a symmetric design. Since a symmetric design has exactly one block intersection number, the resulting design will have two block intersection numbers. Such quasi-symmetric designs are called improper. Only one example of a proper quasi-multiple quasi-symmetric design seems to be known so far. The question of the existence of a quasi-multiple of a symmetric design is of some importance particularly when the corresponding symmetric design is known not to exist. In that case, obtaining a quasi-multiple with least multiplicity has attracted attention of combinatorialists in the last thirty years.
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References
T. Beth, D. Jungnickel and H. Lenz, Design Theory, Cambridge University Press, 1986 and 1999.
A.R. Calderbank and P. Morton, Quasi-symmetric 3-designs and elliptic curves, SIAM J. Discrete Mathematics, 3, 178–196, 1990.
J.D. Fanning, A family of symmetric designs, Discrete Mathematics, 146, 307–312, 1995.
M. Hall, Jr., Combinatorial Theory, John Wiley and Sons (New York), 1986.
Y.J. Ionin, A technique for constructing symmetric designs, Designs, Codes and Cryptography, 14, 147–158, 1998.
Y.J. Ionin, Building symmetric designs with building sets, Designs, Codes and Cryptography, 17, 159–175, 1999.
Y.J. Ionin and M.S. Shrikhande, On a conjecture of Jungnickel and Tonchev for quasi-symmetric designs, Journal of Combinatorial Designs, 2/1, 49–59, 1994.
D. Jungnickel and A. Pott, Differences Sets, an introduction in: Difference Sets, Sequences and their Correlation properties, edited by A. Pott, et al. Kluwer Academic Publishers, Netherlands, 1999.
D. Jungnickel and V.D. Tonchev, Intersection numbers of quasi-multiples of symmetric designs, in: Advances in Finite Geometries and Designs Proceedings of the third Isle of Thorns conference, 1990, J.W.P. Hirschfeld, D.R. Hughes and J. A. Thas (Editors), Oxford University Press, Oxford, 227–236, 1991.
C.W.H. Lam, L. Thiel and S. Swiercz, The non-existence of finite projective planes of order 10, Canadian Journal of Mathematics, XLI(6), 1117–1123, 1989.
R.M. Pawale, Studies in Quasi-Symmetric designs, Ph.D. thesis, University of Bombay, 1989.
R.M. Pawale, Quasi-symmetric 3-designs with triangle-free graph, Geometriae Dedicata, 37/2, 205–210, 1991.
R.M. Pawale and S.S. Sane, A short proof of a conjecture on quasi-symmetric 3-designs, Discrete Mathematics, 76, 71–74, 1991.
D.P. Rajkundlia, Some techniques for constructing infinite families of BIBDs, Discrete Mathematics, 44, 61–96, 1983.
C.R. Rao, Cyclic generation of linear subspaces in finite geometries, in: Combinatorial Mathematics and its Applications, edited by R.C. Bose and T.A. Dowling, University of North Carolina Press, 515–535, 1969.
C.R. Rao, Difference sets and combinatorial arrangements derivable from finite geometries, Proc. Nat. Inst. Sci., India, 12, 125–135, 1946.
S.S. Sane, On a class of symmetric designs, in: Combinatorics and Applications, edited by K.S. Vijayan and N.M. Singhi, Indian Statistical Institute, Calcutta, 292–302, 1982.
S.S. Sane, A proof of the Jungnickel-Tonchev conjecture on quasi-multiple quasi-symmetric designs (to appear in Designs, Codes and Cryptography).
S.S. Sane, Quasi-multiple quasi-symmetric designs corresponding to biplanes, to appear in the proceedings of Southeastern Conference on Combinatorics, Graph Theory and Computing, Boca Raton, Florida, 2000.
S.S. Sane and M.S. Shrikhande, Quasi-symmetric 2, 3 and 4-designs, Combinatorica 7, 291–301,1987.
S.S. Sane and S.S. Shrikhande, ON generalized quasi-residual designs, Journal of Statistical Planning and Inference, 17, 269–276, 1987.
M.S. Shrikhande and S.S. Sane, Quasi-Symmetric Designs, London Math. Society Lecture Notes No. 164, Cambridge University Press, 1991.
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Sane, S. (2002). Some Recent Advances on Symmetric, Quasi-Symmetric and Quasi-Multiple Designs. In: Agarwal, A.K., Berndt, B.C., Krattenthaler, C.F., Mullen, G.L., Ramachandra, K., Waldschmidt, M. (eds) Number Theory and Discrete Mathematics. Hindustan Book Agency, Gurgaon. https://doi.org/10.1007/978-93-86279-10-1_9
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DOI: https://doi.org/10.1007/978-93-86279-10-1_9
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