The Rank of the Semigroup of All Order-Preserving Transformations on a Finite Fence

Vítor H. Fernandes1, Jörg Koppitz2,3, Tiwadee Musunthia4
1CMA, Departamento de Matemática, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
2Institute of Mathematics, University of Potsdam, Potsdam, Germany
3Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Sofia, Bulgaria
4Department of Mathematics, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand

Tóm tắt

A zig-zag (or fence) order is a special partial order on a (finite) set. In this paper, we consider the semigroup $$\mathscr {TF}_{n}$$ of all order-preserving transformations on an n-element zig-zag-ordered set. We determine the rank of $$\mathscr {TF}_{n}$$ and provide a minimal generating set for $$ \mathscr {TF}_{n}$$ . Moreover, a formula for the number of idempotents in $$\mathscr {TF}_{n}$$ is given.

Tài liệu tham khảo

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