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21.147 (2026)

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(V. M. Kopytov, N. Ya. Medvedev). A subgroup $H$ of a right-orderable group $G$ is said to be right-relatively convex if it is convex under some right ordering on $G$. Is the lattice of right-relatively convex subgroups of a right-orderable group always a sublattice of the lattice of its subgroups?

Contributor: A. V. Zenkov

Progress

*No, not always (P. Monticone, Preprint, 2026, https://kourovkanotebookorg.wordpress.com/wp-content/uploads/2026/06/21_147.pdf).

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