Every lattice-ordered group embeds in a lattice-ordered permutation group on one totally ordered set. Choose a value in a lattice-ordered group for each nonidentity element, act on its ordered right cosets, and combine these chains in an order sum. The original element moves its own value's identity coset, making the action faithful. The coset lattice formulas make the embedding preserve both join and meet.
Order n-transitivity 2026-10-14
An ordered permutation group is order n-transitive if it can send any increasing -tuple to any other increasing -tuple. This compares tuples with the same relative order, unlike unrestricted n-transitive group actions. In the usual transitive chain setting, order two-transitivity implies every finite order-transitivity for a lattice-ordered permutation group.
A transitive lattice-ordered permutation group is order-primitive when its only invariant equivalence relations with convex classes are equality and the universal relation. This concerns convex blocks in a chain, rather than arbitrary blocks of a primitive group action.
For each , choose a value in a lattice-ordered group , using Zorn's lemma. Such a value is a prime convex lattice subgroup. Otherwise the last construction in Question 1(i) would give two larger convex lattice subgroups whose intersection is ; maximality among subgroups omitting would put in both, hence in their intersection. Thus the right coset set is a totally ordered set.
Right multiplication defines an action . It is well-defined, preserves the total order, and has inverse . The coset formulas from Question 1(i) show pointwise preservation of both join and meet, because
and likewise for the meet.
Take the disjoint union of these chains, arranged in any fixed order sum of the indices . Let every act on each component by . This gives a lattice-ordered group homomorphism into the order automorphisms of one chain. It is injective: a nonidentity moves the identity coset in , since . Its image is closed under pointwise join and meet, giving exactly the required lattice-ordered permutation group. This is the Holland representation theorem.
Here transitivity is order n-transitivity: increasing tuples are compared, rather than arbitrary reorderings. For increasing tuples and , choose sending both to and to when , using order two-transitivity. For , choose an element sending the single point to its target, using transitivity. Define
Figure 1.
Finite order interpolation constructed from pointwise minima and maxima
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This belongs to the lattice-ordered permutation group. At , all terms in its th inner meet equal . At , every inner meet is at most , because its term takes that value. The outer join is consequently exactly there. Thus maps the whole tuple to its target. This finite interpolation by lattice operations proves every finite order-transitivity without assuming the group permits arbitrary cut-and-paste restrictions of its elements.
The two positive parts satisfy , commute with one another, and have meet one. They isolate positive and negative displacement in the pointwise model of a lattice-ordered permutation group. These are group elements, unlike the scalar positive part of a real number.