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Counterexamples to uniqueness for a discrete X-ray transform under quadratic decay
Abstract
We show nonuniqueness for a discrete X-ray transform on ℤ2 under quadratic decay. We construct an explicit nonzero function in ℓ1(ℤ2) with pointwise decay O(|z|−2) whose sums over integer lines vanish. We also obtain an infinite-dimensional null space with the same decay assumption. Furthermore, we show a result which indicates that the decay rate |z|−2 may be sharp and faster decay may imply uniqueness.
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BibTeX
@misc{jathar2026counterexamples,
title = {{Counterexamples to uniqueness for a discrete X-ray transform under quadratic decay}},
author = {Shubham R. Jathar and Jesse Railo},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.01294},
eprint = {2611.01294},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.01294},
}
RIS
TY - UNPB
TI - Counterexamples to uniqueness for a discrete X-ray transform under quadratic decay
AU - Shubham R. Jathar
AU - Jesse Railo
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.01294
UR - https://arxiv.org/abs/2611.01294
AB - We show nonuniqueness for a discrete X-ray transform on ℤ^2 under quadratic decay. We construct an explicit nonzero function in ℓ^1(ℤ^2) with pointwise decay O(|z|^−2) whose sums over integer lines vanish. We also obtain an infinite-dimensional null space with the same decay assumption. Furthermore, we show a result which indicates that the decay rate |z|^−2 may be sharp and faster decay may imply uniqueness.
ER -