We show that the extension of Presburger arithmetic by a quadratic generalised polynomial of a specific form is undecidable.

@article{paperbot3367,
  title = {Decidability of extensions of Presburger arithmetic by generalised polynomials},
  author = {Jakub Konieczny},
  journal = {Logical Methods in Computer Science},
  volume = {Volume 21, Issue 4},
  year = {2025},
  doi = {10.46298/lmcs-21(4:1)2025}
}