Abstract:
We study maximal and minimal partial orders of the group $\mathrm{Aut}\mathbf Q$ of all order automorphisms of a linearly ordered set $\mathbf Q$ of rational numbers. A proof is given for the fact that $\mathrm{Aut}\mathbf Q$ has 36 distinct minimal non-trivial partial orders, and their complete description is provided in. Also, all maximal partial orders of each of the normal subgroups of $\mathrm{Aut}\mathbf Q$ are described.
Keywords:linearly ordered set of rational numbers, maximal partial order, minimal partial order, order automorphism.