## Abstract We complete the classification of all symmetric designs of order nine admitting an automorphism of order six. As a matter of fact, the classification for the parameters (35,17,8), (56,11,2), and (91,10,1) had already been done, and in this paper we present the results for the parameters
Symmetric (41,16,6)-designs with a nontrivial automorphism of odd order
β Scribed by Edward Spence
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 722 KB
- Volume
- 1
- Category
- Article
- ISSN
- 1063-8539
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β¦ Synopsis
Abstract
If a symmetric (41,16,6)βdesign has an automorphism Ο of odd prime order q then q = 3 or 5. In the case q = 5 we determine all such designs and find a total of 419 nonisomorphic ones, of which 15 are selfβdual. When q = 3 a combinatorial explosion occurs and the complete classification becomes impracticable. However, we give a characterization in the particular case when Ο has order 3 and fixes 11 points, and find that there are 3,076 nonisomorphic designs with this property, all of them being non selfβdual. The other remaining possibility is that Ο, of order 3, fixes 5 points. In this case there are 960 orbit matrices (up to isomorphism and duality) and all but one of them yield designs. Here an incomplete investigation shows that in total there are at least 112,000 nonisomorphic designs. Β© 1993 John Wiley & Sons, Inc.
π SIMILAR VOLUMES
All quasi-symmetric 2-(28, 12, 11) designs with an automorphism of order 7 without fixed points or blocks are enumerated. Up to isomorphism, there are exactly 246 such designs. All but four of these designs are embeddable as derived designs in symmetric 2-(64, 28, 12) designs, producing in this way
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