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On semigroups of ideals and related isomorphism problems

主 讲 人 :Pedro A. García-Sánchez     教授

活动时间:03月19日16时00分    

地      点 :理科群1号楼D203室 (https://zoom.us/j/84035353067?pwd=IbgczC6vqrwhzRNun1RCaRfmaHYWQ1.1 账号:84035353067密码:245733)

讲座内容:

Let $H$ be a monoid (written multiplicatively). A non-empty set $I \subseteq H$ is an ideal if $I = IH = HI$; and is a finitely generated ideal if $I = XH = HY$ for some finite $X, Y \subseteq H$. We call $H$ Archimedean if, for all $a, b \in H$ such that $b$ is a non-unit, there is an integer $k \ge 1$ with $b^k \in HaH$; strongly Archimedean if, for each $a \in H$, there is an integer $k \ge 1$ such that $HaH$ contains any product of any $k$ non-units of $H$; and duo if $aH = Ha$ for all $a \in H$. For instance, commutative monoids are duo and numerical monoids are strongly Archimedean.

We will outline a proof of the following results: (1) The sets of ideals of two strongly Archimedean, cancellative, duo monoids are isomorphic as semigroups under the induced operation of setwise multiplication if and only if the monoids themselves are isomorphic up to units. (2) The same holds upon restriction to finitely generated ideals in Archimedean, cancellative, duo monoids.  

If time permits, we will also discuss how these results can be applied to answer some special cases of an open problem of Kobayashi from the early 1980s.


主讲人介绍:

Pedro A. García-Sánchez defended his PhD thesis at the University of Granada(西班牙格拉纳达大学) (Spain) in 1996, where he has held a permanent position since 1999, became a full professor of algebra in 2017, and has served as the Director for Internationalization at the International School for Postgraduate Studies. His primary research interests include numerical semigroups, commutative monoids, and non-unique factorization. He has served as the principal investigator for several research projects in these areas, and has authored or coauthored four books and approximately one hundred research papers. Additionally, he is an associate editor of Communications in Algebra and has actively participated in various teaching innovation projects.