Generating sets of an infinite semigroup of transformations preserving a zig-zag order

Authors: LADDAWAN LOHAPAN, JÖRG KOPPITZ, SOMNUEK WORAWISET

Abstract: A zig-zag order is like a directed path, only with alternating directions. A generating set of minimal size for the semigroup of all full transformations on a finite set preserving the zig-zag order was determined by Fenandes et al. in 2019. This paper deals with generating sets of the semigroup $F_{\mathbb{N}}$ of all full transformations on the set of all natural numbers preserving the zig-zag order. We prove that $F_{\mathbb{N}}$ has no minimal generating sets and present two particular infinite decreasing chains of generating sets of $F_{\mathbb{N}}.$

Keywords: Fence, zig-zag order, order-preserving, generating set, transformation

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