Abstract
From any directed graph E one can construct the graph inverse semigroup G(E)𝐺(𝐸), whose elements, roughly speaking, correspond to paths in E. Wang and Luo showed that the congruence lattice L(G(E))𝐿(𝐺(𝐸)) of G(E)𝐺(𝐸) is upper-semimodular for every graph E, but can fail to be lower-semimodular for some E. We provide a simple characterization of the graphs E for which L(G(E))𝐿(𝐺(𝐸)) is lower-semimodular. We also describe those E such that L(G(E))𝐿(𝐺(𝐸)) is atomistic, and characterize the minimal generating sets for L(G(E))𝐿(𝐺(𝐸)) when E is finite and simple.
Original language | English |
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Article number | 3 |
Pages (from-to) | 371-396 |
Number of pages | 26 |
Journal | International Journal of Algebra and Computation |
Volume | 34 |
Issue number | 3 |
DOIs | |
Publication status | Published - 20 Apr 2024 |
Bibliographical note
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