Dávid Mezőfi, Gábor P. Nagy
Published 2020-03-20Version 1
The main result of this paper is a general construction which produces new Steiner systems (2-designs) from old ones with the same parameters. We call this construction paramodification of Steiner systems, since it modifies the parallelism of a subsystem. We study in more details the paramodifications of affine planes, Steiner triple systems and unitals. We present computational results which show that many new unitals can be constructed by paramodification.
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