Research
Petrit Isufi · independent researcher · Wuppertal, Germany · ORCID 0009-0004-3834-8704
I work on combinatorial optimisation problems where a result can be checked rather than believed: record graphs, exact optimality certificates, and the verification code that belongs to them. The work is carried out by autonomous AI agents under my direction. Every record is re-verified with independently written checker code, in exact arithmetic, before it is submitted anywhere.
Preprints
- Isufi, P. (2026). A second independent verification of the counterexample to Goemans' unsplittable-flow cost conjecture, and the exact suprema of its three-parameter family. Zenodo. doi:10.5281/zenodo.22238190 · CC BY 4.0
In preparation
- Certified beam-angle optimisation on open radiotherapy benchmarks. Exact rational optimality certificates for beam-angle selection on the open CORT benchmark cases, together with a verifier that re-runs the decisive exclusion step in a browser. Intended for Physics in Medicine & Biology, with a preprint in
physics.med-ph.
Record entries — the degree–diameter problem
Seven cells of the Comellas–Delorme record table (UPC Barcelona) currently stand under my name, all entered in August 2026:
- degree 15, diameter 3 — order 1224
- degree 11, diameter 4 — order 3220
- degree 12, diameter 4 — order 4707
- degree 13, diameter 4 — order 6587
- degree 14, diameter 4 — order 8255
- degree 15, diameter 4 — order 11736
- degree 16, diameter 4 — order 14687
The five diameter-4 entries improve on constructions by Gómez and Fiol from 1985. Each graph was checked twice before submission: once by the unmodified project checker, once by a program written independently for that purpose, deliberately using a different algorithm.
How the results are verified
Three rules, and they are the reason this page exists at all:
- Independent implementation. A second checker written from the specification, by a different author, without sight of the first one. Re-running the same code is not verification.
- Exact arithmetic wherever a certificate is claimed. Floating point is allowed to search; it is not allowed to decide.
- An artefact someone else can re-run. Certificates are published with the data and the checker, not as a claim in prose.