Reference:
Petteri Kaski, Patric R. J. Östergård, Svetlana Topalova, and Rosen Zlatarski. Steiner triple systems of order 19 and 21 with subsystems of order 7. Discrete Mathematics, 308(13):2732–2741, 2008.
Abstract:
Steiner triple systems (STSs) with subsystems of order 7 are classified. For order 19, this classification is complete, but for order 21 it is restricted to Wilson-type systems, which contain three subsystems of order 7 on disjoint point sets. The classified STSs of order 21 are tested for resolvability; none of them is doubly resolvable.
Keywords:
classification, doubly resolvable design, Steiner triple system, subsystem
Suggested BibTeX entry:
@article{KOTZ08,
author = {Petteri Kaski and Patric R. J. {\"O}sterg{\aa}rd and Svetlana Topalova and Rosen Zlatarski},
journal = {Discrete Mathematics},
number = {13},
pages = {2732--2741},
title = {Steiner triple systems of order 19 and 21 with subsystems of order 7},
volume = {308},
year = {2008},
}
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