Abstract
Zappa–Szép products arise when an algebraic structure has the property that every element has a unique decomposition as a product of elements from two given substructures. They may also be constructed from actions of two structures on one another, satisfying axioms first formulated by G. Zappa, and have a natural interpretation within automata theory. We study Zappa–Szép products arising from actions of a group and a band, and study the structure of the semigroup that results. When the band is a semilattice, the Zappa–Szép product is orthodox and ℒ-unipotent. We relate the construction (via automata theory) to the λ-semidirect product of inverse semigroups devised by Billhardt.
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Communicated by László Márki.
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Gilbert, N.D., Wazzan, S. Zappa–Szép products of bands and groups. Semigroup Forum 77, 438–455 (2008). https://doi.org/10.1007/s00233-008-9065-5
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DOI: https://doi.org/10.1007/s00233-008-9065-5