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A Note on a Generating Set for \(N_5^\infty \)

Y. Miao1
1Mathematics Teaching-Research Section Suzhou Institute of Silk Textile Technology Suzhou, 215005, P, R. China

Abstract

In this note, we construct a \((39, \{5,6,7\}, 1)\)-PBD. Thus we have a finite generating set for the PBD-closed set \(N_5^{\infty}\) with at most three inessential elements, where \(N_5^\infty = \{1\} \cup \{v: v \geq 5\}\).