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Principled choice of the infinite unit in hyperreal evaluation

Determine a principled reason for choosing the specific hyperreal @ as the unit by which to measure infinity in starred sums and integrals, thereby justifying the selection of @ and addressing the arbitrariness of this choice.

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Background

The hyperreal summation and integration method requires selecting an infinite bound (such as @) to evaluate divergent sums and integrals. The choice of this infinite unit affects the interpretation of results and may introduce arbitrariness, especially given ultrafilter dependence.

Establishing a principled criterion for selecting @ would help canonize the framework and reduce concerns about arbitrary or non-canonical choices.

References

We currently lack a principled reason for choosing the hyperreal @ as the unit by which to measure the infinite.

Evaluating the Infinite (2509.19389 - Ord, 22 Sep 2025) in Challenges & limitations, item 3 ("Why @ ?")