R. M. Wilson in 《Enumeration and Designs》 (1984) and Th. Beth, D. Jungnickel & H. Lenz in 《Designs Theory》 (1985), raised the following symmetric PBD conjecture.
文摘R. M. Wilson in 《Enumeration and Designs》 (1984) and Th. Beth, D. Jungnickel & H. Lenz in 《Designs Theory》 (1985), raised the following symmetric PBD conjecture.