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arXiv · 2607.18942

Bounded elementary extensions of trees with unbounded paths

Ruaan Kellerman
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Abstract

A tree is a partially ordered set that is downwards linear and downwards connected. A tree is called bounded when each of its paths (i.e. maximal linearly ordered subsets) contains a greatest element. In a bounded tree, each path can be defined by a first-order formula using the leaf of the path as parameter. Bounded trees can be used to model computational systems such as Zeno machines whereby the leaf of a path represents the state to which an infinitely long sequence of computations converges, or a state that is assigned to a computational sequence that loops. We identify a sufficient condition under which certain trees that are not bounded, can be elementarily embedded in trees that are bounded. Several tree operations are also given, and Feferman-Vaught style preservation properties for these operations are proved.

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Ruaan Kellerman. 2026-07-21. Bounded elementary extensions of trees with unbounded paths. https://arxiv.org/abs/2607.18942

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