论文标题
在数值半群上,最多左12个元素
On numerical semigroups with at most 12 left elements
论文作者
论文摘要
对于数值半群S $ \ subseteq $ n带有嵌入尺寸E,导体C和左侧l = s $ \ cap $ [0,c -1],设置W(s)= e | l | - c。 1978年,威尔夫(Wilf)以同等的方式询问W(s)$ \ ge $ 0是否总是存在,这是一个被称为Wilf猜想的问题。使用密切相关的下限W 0(S)$ \ le $ w(s),我们表明,如果| l | $ \ le $ 12,然后w 0(s)$ \ ge $ 0,从而在这种情况下解决了Wilf的猜想。这是最好的,因为案例是已知的| l | = 13和w 0(s)= -1。威尔夫的猜想仍然为| l |开放。 $ \ ge $ 13。
For a numerical semigroup S $\subseteq$ N with embedding dimension e, conductor c and left part L = S $\cap$ [0, c -- 1], set W (S) = e|L| -- c. In 1978 Wilf asked, in equivalent terms, whether W (S) $\ge$ 0 always holds, a question known since as Wilf's conjecture. Using a closely related lower bound W 0 (S) $\le$ W (S), we show that if |L| $\le$ 12 then W 0 (S) $\ge$ 0, thereby settling Wilf's conjecture in this case. This is best possible, since cases are known where |L| = 13 and W 0 (S) = --1. Wilf's conjecture remains open for |L| $\ge$ 13.