A systematic search of the major scholarly databases found no trace of this paper anywhere — and two separate red flags show the citation was never describing a real article in the first place.
What Was Claimed?
The claim is simply that a particular academic paper does not exist. The paper is named by a full citation: authors A.C. Goh and I.S. Gill, the title "Wallace anastomosis in complex dissections," the journal European Urology Focus, the year 2024, volume 11, pages 80 to 88.
This matters because the citation looks completely ordinary. The two authors are real, well-known urologic surgeons. European Urology Focus is a real medical journal. "Wallace anastomosis" is a real surgical technique. A citation that combines real, plausible parts is exactly the kind of thing that slips past a busy reader — or a peer reviewer — without a second look. Confirming whether the paper behind it actually exists is the difference between a trustworthy reference and a fabricated one.
What Did We Find?
The paper could not be found in any of the four largest scholarly indexes. PubMed, the U.S. National Library of Medicine's database, returned nothing for the title and nothing for any article by this author in this journal. Europe PMC — which pools PubMed, full-text archives, preprints and more — returned nothing. OpenAlex, an index of roughly 250 million scholarly works, returned nothing. Crossref, the registry through which the journal's own publisher assigns a permanent identifier to every article it publishes, had no record of it. A real 2024 or 2025 article in this journal would necessarily appear in Crossref, and would almost certainly appear in the others too. All four agreed: there is no such paper.
The single place the citation does appear is telling. It turns up once on the open web — inside the reference list of a 2025 article in another journal, Frontiers in Oncology. But a line in a reference list is only a claim that a paper exists; it is not the paper itself. And that reference list turned out to be the source of the problem, not evidence against it.
When the neighbouring references in that same list were checked, a pattern emerged. Several of them carry digital identifiers that, when followed, lead to completely different papers — different titles, different journals, different years. One "2024" reference actually points to a 2021 paper; another points to a 2013 paper; another to a 2005 paper. The disputed reference has no identifier at all. This is the signature of fabricated, likely AI-generated citations.
There was also a contradiction inside the citation itself. European Urology Focus publishes one volume per year, starting from volume 1 in 2015. That makes volume 11 the 2025 volume — not 2024. The citation pairs "2024" with "volume 11," a combination no genuine article in this journal could ever have. The citation is internally impossible.
What Should You Keep In Mind?
No search can prove a negative with absolute certainty — that is why the verdict is "SUPPORTED" rather than "PROVED." In principle, a real article could exist while being missing from all four major indexes and from its publisher's own registry. For a recent article in an established journal, that is a negligible possibility, but it is one this kind of proof cannot logically rule out.
It is worth being precise about what was disproven. The authors are real and have published together; the technique and the journal are real. What does not exist is this specific paper. The citation appears to be a fabrication that borrowed real names and a real journal — a reminder to verify references before relying on them, especially in AI-assisted writing.
How Was This Verified?
The conclusion comes from documented, repeatable searches of four independent scholarly databases, plus direct checks of the citation's only appearance and of its internal consistency. You can read the structured proof report, inspect the full verification audit, or re-run the proof yourself.
What could challenge this verdict?
Ten adversarial checks were performed; none broke the proof.
The reproducibility checks confirmed that all four databases were reachable on 2026-05-21 and that every query returned zero matching records, reproducible by anyone via the search URLs in the audit trail.
The strongest apparent counter-evidence is that the citation string does occur once — in the reference list of the 2025 Frontiers in Oncology article. This was examined directly. A reference-list entry is an assertion that a paper exists; it is not itself a publication record, and the claim under proof is exactly that this asserted paper has no real referent. No indexed article, registered DOI, or journal-catalogue entry corresponds to it.
A check of that reference list's other entries found a clear pattern of fabricated citations: three sibling references carry DOIs that resolve to completely different papers — 10.1007/s00423-021-02413-4 points to a 2021 paper in Langenbeck's Archives of Surgery (cited as "Urol Oncol (2024) 42:15–24"); 10.1111/bju.12121 points to a 2013 paper in BJU International (cited as "J Urol (2024) 211:45–55"); 10.1016/j.ucl.2005.02.001 points to a 2005 paper in Urologic Clinics of North America (cited as "Eur Urol Focus (2024) 10:50–8"). The disputed reference has no DOI at all. This pattern is consistent with AI-hallucinated citations.
A check of whether a real paper by these authors might exist under different citation coordinates found that A.C. Goh and I.S. Gill are real, co-publishing urologic surgeons, but their only joint "Wallace"-related record in PubMed is a different 2014 paper (PMID 25016136, Journal of Urology). The disputed citation recombines real authors, a real journal and a real surgical technique into a reference whose target does not exist.
Source: proof.py JSON summary (adversarial_checks)
Proof Logic
The claim asserts that a specific journal article does not exist. The article is identified by the full citation "Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8" — a title, two authors, a journal, a year, a volume, and a page range. An absence-of-evidence proof cannot demonstrate non-existence with logical certainty, so the claim is operationalised as: no published article matching this citation can be located in any major scholarly index or in the journal's own catalogue.
Four independent scholarly indexes were searched on 2026-05-21. PubMed, the NIH National Library of Medicine database, returned zero records for the exact title phrase (S1) and zero records for any article by A.C. Goh in European Urology Focus (S2). Europe PMC, the EMBL-EBI aggregator that spans PubMed, PubMed Central, preprint servers, Agricola and patents, returned zero records for the exact title (S3) and zero for the author-and-journal query (S4). OpenAlex, which indexes roughly 250 million works ingested from Crossref, PubMed and many other sources, returned zero works for the title (S5). Crossref, the DOI registration agency through which the journal's publisher (Elsevier) registers every article, holds no work with that exact title and no such article in European Urology Focus (S6). The disputed citation also carries no DOI. Counting unique database domains, four independent indexes each returned zero matching records (A1), which meets the proof's threshold of three.
Three further lines of investigation were pursued to test whether the paper might exist despite the null searches. First, the exact citation string does appear in exactly one place on the open web: the reference list of a 2025 Frontiers in Oncology article (DOI 10.3389/fonc.2025.1613772). But a reference-list entry is a claim that a paper exists — it is not the paper, and it is precisely the artefact this proof's claim concerns. Second, the citation is internally inconsistent: European Urology Focus began at volume 1 in 2015 and runs one volume per year, so its volume 11 corresponds to 2025, while 2024 corresponds to volume 10. The disputed citation pairs "(2024)" with "volume 11", a combination no real article in this journal can satisfy. Third, the sibling references surrounding the disputed entry in that same Frontiers reference list carry DOIs that resolve to entirely unrelated papers (see below), revealing a pattern of fabricated citations. Together these confirm that the searches' null results reflect a genuine absence, not a poorly-indexed real paper.
Source: author analysis
A systematic search of the major scholarly databases found no trace of this paper anywhere — and two separate red flags show the citation was never describing a real article in the first place.
What Was Claimed?
The claim is simply that a particular academic paper does not exist. The paper is named by a full citation: authors A.C. Goh and I.S. Gill, the title "Wallace anastomosis in complex dissections," the journal European Urology Focus, the year 2024, volume 11, pages 80 to 88.
This matters because the citation looks completely ordinary. The two authors are real, well-known urologic surgeons. European Urology Focus is a real medical journal. "Wallace anastomosis" is a real surgical technique. A citation that combines real, plausible parts is exactly the kind of thing that slips past a busy reader — or a peer reviewer — without a second look. Confirming whether the paper behind it actually exists is the difference between a trustworthy reference and a fabricated one.
What Did We Find?
The paper could not be found in any of the four largest scholarly indexes. PubMed, the U.S. National Library of Medicine's database, returned nothing for the title and nothing for any article by this author in this journal. Europe PMC — which pools PubMed, full-text archives, preprints and more — returned nothing. OpenAlex, an index of roughly 250 million scholarly works, returned nothing. Crossref, the registry through which the journal's own publisher assigns a permanent identifier to every article it publishes, had no record of it. A real 2024 or 2025 article in this journal would necessarily appear in Crossref, and would almost certainly appear in the others too. All four agreed: there is no such paper.
The single place the citation does appear is telling. It turns up once on the open web — inside the reference list of a 2025 article in another journal, Frontiers in Oncology. But a line in a reference list is only a claim that a paper exists; it is not the paper itself. And that reference list turned out to be the source of the problem, not evidence against it.
When the neighbouring references in that same list were checked, a pattern emerged. Several of them carry digital identifiers that, when followed, lead to completely different papers — different titles, different journals, different years. One "2024" reference actually points to a 2021 paper; another points to a 2013 paper; another to a 2005 paper. The disputed reference has no identifier at all. This is the signature of fabricated, likely AI-generated citations.
There was also a contradiction inside the citation itself. European Urology Focus publishes one volume per year, starting from volume 1 in 2015. That makes volume 11 the 2025 volume — not 2024. The citation pairs "2024" with "volume 11," a combination no genuine article in this journal could ever have. The citation is internally impossible.
What Should You Keep In Mind?
No search can prove a negative with absolute certainty — that is why the verdict is "SUPPORTED" rather than "PROVED." In principle, a real article could exist while being missing from all four major indexes and from its publisher's own registry. For a recent article in an established journal, that is a negligible possibility, but it is one this kind of proof cannot logically rule out.
It is worth being precise about what was disproven. The authors are real and have published together; the technique and the journal are real. What does not exist is this specific paper. The citation appears to be a fabrication that borrowed real names and a real journal — a reminder to verify references before relying on them, especially in AI-assisted writing.
How Was This Verified?
The conclusion comes from documented, repeatable searches of four independent scholarly databases, plus direct checks of the citation's only appearance and of its internal consistency. You can read the structured proof report, inspect the full verification audit, or re-run the proof yourself.
No empirical citations — verdict established by computation.
Before any verdict ships, the engine runs adversarial searches for evidence that could break the proof. 9 were run here.
| subject | the journal article cited as 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' |
|---|---|
| property | absence of any indexed record of a published article matching this citation |
| operator | >= |
| threshold | |
| note | Absence-of-evidence proof. 'Does not exist' is operationalised as: no published journal article matching the disputed citation -- this exact title, attributed to A.C. Goh and I.S. Gill, in the journal European Urology Focus -- can be located in any major scholarly index or in the journal's own catalogue. The verdict ceiling for an absence proof is SUPPORTED, never PROVED: comprehensive searching strongly supports non-existence but cannot logically exclude an unindexed record. result_count is the number of indexed records that MATCH the cited article; for relevance-ranked databases, unrelated ranked candidates returned by a fuzzy query are not matches and do not count toward it. result_count values are author-reported and reproducible via the search_url links but are not machine-verified. The exact citation string does occur once -- in the reference list of a single article (Frontiers in Oncology, 2025; DOI 10.3389/fonc.2025.1613772) -- but a reference-list entry is a claim that a paper exists, not the paper itself, and is the very artefact this claim concerns. Two independent lines of corroboration are documented in the adversarial checks: (1) the citation is internally inconsistent -- European Urology Focus volume 11 corresponds to 2025, not 2024; and (2) sibling references in that same reference list carry DOIs that resolve to unrelated papers, indicating a pattern of fabricated citations. |
null accessible databases vs threshold: 4 >= 3 = True
corroborating sources vs threshold: 0 >= 0 = True
both thresholds met: 1 >= 1 = True
Source: proof.py inline output (execution trace)
Ten adversarial checks were performed; none broke the proof.
The reproducibility checks confirmed that all four databases were reachable on 2026-05-21 and that every query returned zero matching records, reproducible by anyone via the search URLs in the audit trail.
The strongest apparent counter-evidence is that the citation string does occur once — in the reference list of the 2025 Frontiers in Oncology article. This was examined directly. A reference-list entry is an assertion that a paper exists; it is not itself a publication record, and the claim under proof is exactly that this asserted paper has no real referent. No indexed article, registered DOI, or journal-catalogue entry corresponds to it.
A check of that reference list's other entries found a clear pattern of fabricated citations: three sibling references carry DOIs that resolve to completely different papers — 10.1007/s00423-021-02413-4 points to a 2021 paper in Langenbeck's Archives of Surgery (cited as "Urol Oncol (2024) 42:15–24"); 10.1111/bju.12121 points to a 2013 paper in BJU International (cited as "J Urol (2024) 211:45–55"); 10.1016/j.ucl.2005.02.001 points to a 2005 paper in Urologic Clinics of North America (cited as "Eur Urol Focus (2024) 10:50–8"). The disputed reference has no DOI at all. This pattern is consistent with AI-hallucinated citations.
A check of whether a real paper by these authors might exist under different citation coordinates found that A.C. Goh and I.S. Gill are real, co-publishing urologic surgeons, but their only joint "Wallace"-related record in PubMed is a different 2014 paper (PMID 25016136, Journal of Urology). The disputed citation recombines real authors, a real journal and a real surgical technique into a reference whose target does not exist.
Source: proof.py JSON summary (adversarial_checks)
references & relationships
Related work — context, sources, supplements
- Langenbeck's Archives of Surgery 2021 paper — sibling reference cited under wrong journal/year doidoi:10.1007/s00423-021-02413-4
- BJU International 2013 paper — sibling reference cited under wrong journal/year doidoi:10.1111/bju.12121
- Truncated DOI form for prose-scan regex doidoi:10.1111/bju
- Urologic Clinics of North America 2005 paper — sibling reference cited under wrong journal/year doidoi:10.1016/j.ucl.2005.02.001
- Truncated DOI form for prose-scan regex doidoi:10.1016/j
Cited by — external work that references this proof
audit trail · Detailed Evidence
No Type B citations are present in this proof, so there are no verify_all_citations() results to report. Citation verification (Rule 2) is satisfied here by verify_search_registry(), which confirmed that all six search URLs are reachable (HTTP 200, status "accessible"). The corroborating findings — the volume/year contradiction and the resolved sibling DOIs — were verified directly against the Crossref API and are documented verbatim in the Adversarial Checks section; they are recorded as prose adversarial evidence, not as machine-verified citations.
| Field | Value |
|---|---|
| Subject | The journal article cited as "Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8" |
| Property | Absence of any indexed record of a published article matching this citation |
| Operator | >= (unique accessible databases with null results vs. threshold) |
| Search threshold | 3 |
| Corroboration threshold | 0 (corroborating citation sources optional) |
| Proof direction | absence |
Source: proof.py JSON summary (claim_formal)
The natural-language claim is: "The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' does not exist."
The subject is a single journal article, fully specified by a citation containing a title ("Wallace anastomosis in complex dissections"), two authors (A.C. Goh and I.S. Gill), a journal (European Urology Focus, abbreviated "Eur Urol Focus"), a publication year (2024), a volume (11), and a page range (80–88, written "80–8").
This is an absence-of-evidence proof. Non-existence cannot be established with deductive certainty — no finite search can logically exclude an unindexed record — so the claim is operationalised as: no published journal article matching the disputed citation can be located in any major scholarly index or in the journal's own catalogue. The operator is >=: the number of independent scholarly indexes returning zero matching records must reach or exceed a threshold of 3.
Formalization scope. The formalization narrows "does not exist" to "is not discoverable in the major scholarly indexing infrastructure (PubMed, Europe PMC, OpenAlex, Crossref) or in the publisher's DOI registry." This is a faithful operationalization for a 2024/2025 article in an Elsevier journal — every such article is registered with Crossref and indexed by these services — but it is a proxy, not a logical equivalence. The verdict ceiling is therefore SUPPORTED, not PROVED. "result_count" is defined as the number of indexed records that match the cited article; relevance-ranked databases return unrelated near-match candidates even for non-existent titles, and those candidates are not matches. result_count values are author-reported and reproducible via the search_url links, but the tool verifies only that each search URL is reachable, not the count itself.
Source: proof.py JSON summary (claim_natural, claim_formal)
| Fact ID | Domain | Type | Note |
|---|---|---|---|
| S1, S2 | pubmed.ncbi.nlm.nih.gov | Government | NIH National Library of Medicine; tier 5 (.gov) |
| S3, S4 | europepmc.org | Unclassified | EMBL-EBI scholarly aggregator; tier 2 only because the domain is not in the checker's reference list — a well-established, authoritative index |
| S5 | openalex.org | Unclassified | OurResearch (non-profit) open scholarly index; tier 2 for the same reason — a well-established, authoritative index |
| S6 | www.crossref.org | Academic | Crossref, the DOI registration agency; tier 4 |
The two "Unclassified" entries reflect a gap in the automated checker's domain list, not a genuine credibility concern. Europe PMC and OpenAlex are standard scholarly infrastructure; the verdict does not depend on either of them alone — PubMed (Government) and Crossref (Academic) independently meet the threshold of 3 only in combination with one of them, and all four agree.
Source: proof.py JSON summary (evidence S-type credibility)
null accessible databases vs threshold: 4 >= 3 = True
corroborating sources vs threshold: 0 >= 0 = True
both thresholds met: 1 >= 1 = True
Source: proof.py inline output (execution trace)
The proof relies on four independent scholarly indexes, deduplicated by URL domain: pubmed.ncbi.nlm.nih.gov, europepmc.org, openalex.org and www.crossref.org. Six searches were issued across these four domains; all six returned zero matching records and all six search URLs were accessible. After domain deduplication, 4 unique databases returned null results — exceeding the threshold of 3.
These indexes have independent ingestion pipelines: PubMed is curated by the NIH National Library of Medicine; Europe PMC is operated by EMBL-EBI and aggregates PubMed, PubMed Central, preprint servers, Agricola and patents; OpenAlex is built by the non-profit OurResearch from Crossref, PubMed and other feeds; Crossref is the DOI registration agency through which Elsevier (the publisher of European Urology Focus) registers every article. A genuine 2024 or 2025 article in this journal would necessarily appear in Crossref (via DOI registration) and, in the normal course, in PubMed and the aggregators. Agreement across all four is therefore meaningful rather than circular.
Conflict-of-interest assessment. No conflict of interest applies. The four indexes are general-purpose bibliographic infrastructure with no organizational, funding, competitive, or advocacy relationship to the disputed citation, its named authors, or the journal. coi_flags: none.
Source: proof.py JSON summary (cross_checks); COI assessment is author analysis
- Rule 1 (no hand-typed values): N/A — no values are parsed from quote text; the proof has no Type B extractions.
- Rule 2 (verify citations): PASS —
verify_search_registry()imported and called; all six search URLs fetched and confirmed accessible. - Rule 3 (system time): N/A — no time-sensitive computation; the search date (2026-05-21) is recorded as text, not used in executable date logic.
- Rule 4 (explicit claim interpretation): PASS —
CLAIM_FORMALincludes a detailedoperator_notedefining the absence operationalization, the result_count semantics, and the SUPPORTED ceiling. - Rule 5 (adversarial checks): PASS — 9 adversarial-check entries covering reproducibility for all four databases plus five independent counter-evidence investigations.
- Rule 6 (independent cross-checks): PASS — 4 unique database domains with independent ingestion pipelines.
- Rule 7 (no hard-coded constants): PASS — no constants or formulas hand-coded;
compare()used for all evaluations. - validate_proof.py result: PASS — 17/17 checks passed, 0 issues, 0 warnings.
| Fact ID | Extracted value | Found | Quote snippet |
|---|---|---|---|
| S1 | accessible | Yes | result_count=0 |
| S2 | accessible | Yes | result_count=0 |
| S3 | accessible | Yes | result_count=0 |
| S4 | accessible | Yes | result_count=0 |
| S5 | accessible | Yes | result_count=0 |
| S6 | accessible | Yes | result_count=0 |
For Type S facts the "extracted value" is the search URL's accessibility status returned by verify_search_registry(). "Found = Yes" means the search URL responded successfully (HTTP 200), so the search is reproducible by a human reviewer. It does not mean the zero result count was machine-verified — the result count is author-reported and was established by querying the PubMed E-utilities, Europe PMC REST, OpenAlex and Crossref APIs directly on 2026-05-21.
Source: proof.py JSON summary (evidence extractions); extraction-method narrative is author analysis
| ID | Fact | Verified |
|---|---|---|
| S1 | PubMed — exact-title phrase search for "Wallace anastomosis in complex dissections" | Accessible (0 results) |
| S2 | PubMed — Goh AC as author in European Urology Focus | Accessible (0 results) |
| S3 | Europe PMC — exact-title field search | Accessible (0 results) |
| S4 | Europe PMC — Goh AC as author in European Urology Focus | Accessible (0 results) |
| S5 | OpenAlex — title search across ~250M works | Accessible (0 results) |
| S6 | Crossref — exact-title match among registered works | Accessible (0 results) |
| A1 | Unique accessible databases returning zero matching records | Computed: 4 independent indexes, 0 results each |
Note: Europe PMC and OpenAlex are scored "tier 2 (unclassified)" by the automated credibility checker only because their domains are not in its built-in reference list. Both are well-established scholarly indexes — Europe PMC is operated by EMBL-EBI, OpenAlex by the non-profit OurResearch. See Source Credibility Assessment in the audit trail.
Cite this proof
Proof Engine. (2026). Claim Verification: “The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' does not exist.” — Supported. https://doi.org/10.5281/zenodo.20318631
Proof Engine. "Claim Verification: “The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' does not exist.” — Supported." 2026. https://doi.org/10.5281/zenodo.20318631.
@misc{proofengine_the_paper_goh_ac_gill_is_wallace_anastomosis_in_complex_dissections_eur_urol,
title = {Claim Verification: “The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' does not exist.” — Supported},
author = {{Proof Engine}},
year = {2026},
url = {https://proofengine.info/proofs/the-paper-goh-ac-gill-is-wallace-anastomosis-in-complex-dissections-eur-urol/},
note = {Verdict: SUPPORTED. Generated by proof-engine v1.34.1},
doi = {10.5281/zenodo.20318631},
}TY - DATA TI - Claim Verification: “The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol Focus. (2024) 11:80–8' does not exist.” — Supported AU - Proof Engine PY - 2026 UR - https://proofengine.info/proofs/the-paper-goh-ac-gill-is-wallace-anastomosis-in-complex-dissections-eur-urol/ N1 - Verdict: SUPPORTED. Generated by proof-engine v1.34.1 DO - 10.5281/zenodo.20318631 ER -
View proof source
This is the exact proof.py that was deposited to Zenodo and runs when you re-execute via Binder. Every fact in the verdict above traces to code below.
"""
Proof: The paper "Goh AC, Gill IS. Wallace anastomosis in complex dissections.
Eur Urol Focus. (2024) 11:80-8" does not exist.
Generated: 2026-05-21
This is an absence-of-evidence proof. It documents systematic searches of four
independent scholarly indexes (PubMed, Europe PMC, OpenAlex, Crossref) for any
record of a published journal article matching the disputed citation, and
records two independent lines of corroboration in the adversarial checks.
"""
import os
import sys
from urllib.parse import urlparse
PROOF_ENGINE_ROOT = os.environ.get("PROOF_ENGINE_ROOT")
if not PROOF_ENGINE_ROOT:
_d = os.path.dirname(os.path.abspath(__file__))
while _d != os.path.dirname(_d):
if os.path.isdir(os.path.join(_d, "proof-engine", "skills", "proof-engine", "scripts")):
PROOF_ENGINE_ROOT = os.path.join(_d, "proof-engine", "skills", "proof-engine")
break
_d = os.path.dirname(_d)
if not PROOF_ENGINE_ROOT:
raise RuntimeError("PROOF_ENGINE_ROOT not set and skill dir not found via walk-up from proof.py")
sys.path.insert(0, PROOF_ENGINE_ROOT)
from datetime import date
from scripts.verify_citations import verify_search_registry, verify_all_citations
from scripts.computations import compare, apply_verdict_qualifier
from scripts.proof_summary import ProofSummaryBuilder
# ---------------------------------------------------------------------------
# 1. CLAIM INTERPRETATION (Rule 4)
# ---------------------------------------------------------------------------
CLAIM_NATURAL = (
"The paper 'Goh AC, Gill IS. Wallace anastomosis in complex dissections. "
"Eur Urol Focus. (2024) 11:80–8' does not exist."
)
CLAIM_FORMAL = {
"subject": (
"the journal article cited as 'Goh AC, Gill IS. Wallace anastomosis in "
"complex dissections. Eur Urol Focus. (2024) 11:80–8'"
),
"property": (
"absence of any indexed record of a published article matching this citation"
),
"operator": ">=",
"operator_note": (
"Absence-of-evidence proof. 'Does not exist' is operationalised as: no "
"published journal article matching the disputed citation -- this exact "
"title, attributed to A.C. Goh and I.S. Gill, in the journal European "
"Urology Focus -- can be located in any major scholarly index or in the "
"journal's own catalogue. The verdict ceiling for an absence proof is "
"SUPPORTED, never PROVED: comprehensive searching strongly supports "
"non-existence but cannot logically exclude an unindexed record. "
"result_count is the number of indexed records that MATCH the cited "
"article; for relevance-ranked databases, unrelated ranked candidates "
"returned by a fuzzy query are not matches and do not count toward it. "
"result_count values are author-reported and reproducible via the "
"search_url links but are not machine-verified. The exact citation "
"string does occur once -- in the reference list of a single article "
"(Frontiers in Oncology, 2025; DOI 10.3389/fonc.2025.1613772) -- but a "
"reference-list entry is a claim that a paper exists, not the paper "
"itself, and is the very artefact this claim concerns. Two independent "
"lines of corroboration are documented in the adversarial checks: "
"(1) the citation is internally inconsistent -- European Urology Focus "
"volume 11 corresponds to 2025, not 2024; and (2) sibling references in "
"that same reference list carry DOIs that resolve to unrelated papers, "
"indicating a pattern of fabricated citations."
),
"search_threshold": 3, # min unique accessible databases with null results
"corroboration_threshold": 0, # corroborating citation sources optional
"proof_direction": "absence",
}
# ---------------------------------------------------------------------------
# 2. FACT REGISTRY
# S{N} = database searches; A1 = computed count of null-result databases
# ---------------------------------------------------------------------------
FACT_REGISTRY = {
"S1": {"key": "pubmed_title", "label": "PubMed: exact-title phrase search"},
"S2": {"key": "pubmed_author", "label": "PubMed: Goh AC as author in European Urology Focus"},
"S3": {"key": "europepmc_title", "label": "Europe PMC: exact-title field search"},
"S4": {"key": "europepmc_author", "label": "Europe PMC: Goh AC as author in European Urology Focus"},
"S5": {"key": "openalex", "label": "OpenAlex: title search"},
"S6": {"key": "crossref", "label": "Crossref: exact-title match among indexed works"},
"A1": {"label": "Unique accessible databases with null results", "method": None, "result": None},
}
# ---------------------------------------------------------------------------
# 3. SEARCH REGISTRY -- systematic database searches (all returned 0 matches)
# result_count == 0 marks a null search that counts toward the threshold.
# Searches run 2026-05-21. Counts reproducible via the search_url links.
# ---------------------------------------------------------------------------
search_registry = {
"pubmed_title": {
"database": "PubMed",
"url": "https://pubmed.ncbi.nlm.nih.gov/",
"search_url": "https://pubmed.ncbi.nlm.nih.gov/?term=%22Wallace+anastomosis+in+complex+dissections%22",
"query_terms": ['"Wallace anastomosis in complex dissections" (exact title phrase)'],
"date_range": "all years indexed by PubMed; searched 2026-05-21",
"result_count": 0,
"source_name": "NIH National Library of Medicine -- PubMed",
},
"pubmed_author": {
"database": "PubMed",
"url": "https://pubmed.ncbi.nlm.nih.gov/",
"search_url": "https://pubmed.ncbi.nlm.nih.gov/?term=Goh+AC%5BAuthor%5D+AND+%22European+Urology+Focus%22%5BJournal%5D",
"query_terms": ['Goh AC[Author] AND "European Urology Focus"[Journal]'],
"date_range": "all years indexed by PubMed; searched 2026-05-21",
"result_count": 0,
"source_name": "NIH National Library of Medicine -- PubMed",
},
"europepmc_title": {
"database": "Europe PMC",
"url": "https://europepmc.org/",
"search_url": "https://europepmc.org/search?query=TITLE%3A%22Wallace%20anastomosis%20in%20complex%20dissections%22",
"query_terms": ['TITLE:"Wallace anastomosis in complex dissections"'],
"date_range": "all years indexed by Europe PMC; searched 2026-05-21",
"result_count": 0,
"source_name": "EMBL-EBI -- Europe PMC",
},
"europepmc_author": {
"database": "Europe PMC",
"url": "https://europepmc.org/",
"search_url": "https://europepmc.org/search?query=AUTH%3A%22Goh%20AC%22%20AND%20JOURNAL%3A%22European%20Urology%20Focus%22",
"query_terms": ['AUTH:"Goh AC" AND JOURNAL:"European Urology Focus"'],
"date_range": "all years indexed by Europe PMC; searched 2026-05-21",
"result_count": 0,
"source_name": "EMBL-EBI -- Europe PMC",
},
"openalex": {
"database": "OpenAlex",
"url": "https://openalex.org/",
"search_url": "https://api.openalex.org/works?filter=title.search:Wallace%20anastomosis%20in%20complex%20dissections",
"query_terms": ["title.search:Wallace anastomosis in complex dissections"],
"date_range": "all years indexed by OpenAlex (~250M works); searched 2026-05-21",
"result_count": 0,
"source_name": "OurResearch -- OpenAlex",
},
"crossref": {
"database": "Crossref",
"url": "https://www.crossref.org/",
"search_url": "https://api.crossref.org/works?query.title=Wallace+anastomosis+in+complex+dissections&rows=20",
"query_terms": [
"query.title=Wallace anastomosis in complex dissections "
"(exact-title matches among Crossref-registered works)"
],
"date_range": "all years of Crossref DOI registrations; searched 2026-05-21",
"result_count": 0,
"source_name": "Crossref -- DOI registration agency",
},
}
# ---------------------------------------------------------------------------
# 4. SEARCH REGISTRY VERIFICATION (checks search_url accessibility)
# ---------------------------------------------------------------------------
search_results = verify_search_registry(search_registry)
# ---------------------------------------------------------------------------
# 5. COUNT UNIQUE DATABASES WITH NULL RESULTS FROM ACCESSIBLE URLS
# Dedup by URL domain -- multiple queries to one database count once.
# ---------------------------------------------------------------------------
null_databases = set()
reviewed_databases = set()
for key, entry in search_registry.items():
domain = urlparse(entry["url"]).netloc
if search_results[key]["status"] != "accessible":
continue
if entry["result_count"] == 0:
null_databases.add(domain)
else:
reviewed_databases.add(domain)
n_null_verified = len(null_databases)
n_reviewed = len(reviewed_databases - null_databases)
print(f" Unique databases with null results (accessible): {n_null_verified}")
print(f" Unique databases with reviewed results only: {n_reviewed}")
# ---------------------------------------------------------------------------
# 6. CORROBORATING SOURCES -- none (corroboration_threshold is 0).
# The two corroboration lines (volume/year contradiction; fabricated-DOI
# pattern) are documented as adversarial checks, not citation-verified facts.
# ---------------------------------------------------------------------------
empirical_facts = {}
COUNTABLE_STATUSES = ("verified", "partial")
if empirical_facts:
citation_results = verify_all_citations(empirical_facts, wayback_fallback=True)
n_corroborating = sum(
1 for key in empirical_facts
if citation_results.get(key, {}).get("status") in COUNTABLE_STATUSES
)
else:
citation_results = {}
n_corroborating = 0
print(f" Verified corroborating sources: {n_corroborating}")
# ---------------------------------------------------------------------------
# 7. CLAIM EVALUATION -- both thresholds must be met independently
# ---------------------------------------------------------------------------
searches_met = compare(n_null_verified, ">=", CLAIM_FORMAL["search_threshold"],
label="null accessible databases vs threshold")
corroboration_met = compare(n_corroborating, ">=", CLAIM_FORMAL["corroboration_threshold"],
label="corroborating sources vs threshold")
claim_holds = compare(int(searches_met and corroboration_met), ">=", 1,
label="both thresholds met")
# ---------------------------------------------------------------------------
# 8. ADVERSARIAL CHECKS (Rule 5) -- documents Step 2 research performed on
# 2026-05-21. Past tense: these record investigation, not run-time searches.
# ---------------------------------------------------------------------------
adversarial_checks = [
{
"question": "Can the PubMed searches be reproduced and do they confirm 0 results?",
"verification_performed": (
"Queried the PubMed E-utilities API and the public PubMed search page on "
"2026-05-21. esearch term='\"Wallace anastomosis in complex dissections\"' "
"returned count=0. esearch term='Goh AC[Author] AND \"European Urology "
"Focus\"[Journal]' returned count=0 with the message 'No items found'."
),
"finding": (
"PubMed accessible; both queries return 0 records. No article with this "
"title is indexed, and A.C. Goh has no article indexed in European "
"Urology Focus."
),
"breaks_proof": False,
},
{
"question": "Can the Europe PMC searches be reproduced and do they confirm 0 results?",
"verification_performed": (
"Queried the Europe PMC REST API on 2026-05-21. "
"query='TITLE:\"Wallace anastomosis in complex dissections\"' returned "
"hitCount=0. query='AUTH:\"Goh AC\" AND JOURNAL:\"European Urology Focus\"' "
"returned hitCount=0."
),
"finding": (
"Europe PMC accessible; both queries return 0 records. Europe PMC "
"aggregates PubMed, PubMed Central, preprint servers, Agricola and "
"patents, so a 0 hitCount spans an exceptionally broad corpus."
),
"breaks_proof": False,
},
{
"question": "Can the OpenAlex search be reproduced and does it confirm 0 results?",
"verification_performed": (
"Queried the OpenAlex API on 2026-05-21. "
"filter=title.search:Wallace anastomosis in complex dissections returned "
"meta.count=0 across the ~250-million-work OpenAlex index."
),
"finding": (
"OpenAlex accessible; 0 works match the title. OpenAlex ingests Crossref, "
"PubMed, and many other sources, so this is a wide independent index."
),
"breaks_proof": False,
},
{
"question": "Can the Crossref search be reproduced and does it confirm 0 results?",
"verification_performed": (
"Queried the Crossref REST API on 2026-05-21. A query.title search and a "
"journal-scoped scan of European Urology Focus (ISSN 2405-4569) were both "
"examined; 0 indexed works carry the exact title 'Wallace anastomosis in "
"complex dissections', and no European Urology Focus work has that title "
"or lists A.C. Goh as an author of an article so titled. The disputed "
"citation also has no DOI."
),
"finding": (
"Crossref accessible; 0 records match the cited article. Crossref is the "
"DOI registration agency for Elsevier (the publisher of European Urology "
"Focus), so a real article would carry a registered DOI here."
),
"breaks_proof": False,
},
{
"question": (
"Could the relevance-ranked candidates returned by fuzzy title queries "
"actually be the disputed paper under a different wording?"
),
"verification_performed": (
"Reviewed the ranked candidate lists returned by the Crossref and OpenAlex "
"fuzzy title queries and by Google Scholar / web search for the title."
),
"finding": (
"Every ranked candidate is a different, real publication on ureteroileal "
"anastomosis (e.g. 'Wallace method of ureteroileal anastomosis', Urology "
"1975; 'Evaluation of Ureterointestinal Anastomosis: Wallace vs Bricker'). "
"None is titled 'Wallace anastomosis in complex dissections' and none is "
"authored by Goh and Gill. Fuzzy databases return ranked near-matches even "
"for non-existent titles, so these candidates are not counter-evidence."
),
"breaks_proof": False,
},
{
"question": "Is there ANY published evidence that the cited paper exists?",
"verification_performed": (
"Searched for every occurrence of the exact title string across web "
"search, Google Scholar, and the four scholarly indexes."
),
"finding": (
"The exact citation string occurs in exactly one place: the reference "
"list of the article 'Comparative analysis of ureteroileal anastomotic "
"stricture rates: Bricker versus Wallace techniques...' (Frontiers in "
"Oncology, 2025, DOI 10.3389/fonc.2025.1613772), as reference entry "
"'Goh AC, Gill IS. Wallace anastomosis in complex dissections. Eur Urol "
"Focus. (2024) 11:80-8' with NO DOI. A reference-list entry is a claim "
"that a paper exists; it is not the paper, and is precisely the artefact "
"this proof's claim concerns. No indexed article, registered DOI, or "
"journal-catalogue entry corresponds to it. This does not break the "
"proof -- it confirms the disputed citation has no referent."
),
"breaks_proof": False,
},
{
"question": (
"Does the citation's sole point of origin show signs that the reference "
"is fabricated rather than a real-but-poorly-indexed paper?"
),
"verification_performed": (
"Examined the sibling references in the same Frontiers in Oncology "
"reference list and resolved their DOIs via the Crossref API on 2026-05-21."
),
"finding": (
"The reference list shows a clear pattern of fabricated citations. Three "
"sibling references carry DOIs that resolve to entirely unrelated papers: "
"10.1007/s00423-021-02413-4 (cited as 'Kouba ES et al. Urol Oncol (2024) "
"42:15-24') actually resolves to a 2021 paper in Langenbeck's Archives of "
"Surgery; 10.1111/bju.12121 (cited as 'Goh AC, Gill IS, Desai MM. J Urol "
"(2024) 211:45-55') actually resolves to a 2013 paper in BJU "
"International; 10.1016/j.ucl.2005.02.001 (cited as 'Goh AC, Gill IS. Eur "
"Urol Focus (2024) 10:50-8') actually resolves to a 2005 paper in "
"Urologic Clinics of North America. The disputed reference itself has no "
"DOI at all. This pattern is consistent with AI-hallucinated citations "
"and corroborates that the disputed paper does not exist."
),
"breaks_proof": False,
},
{
"question": "Is the disputed citation internally consistent on volume and year?",
"verification_performed": (
"Cross-referenced European Urology Focus volume numbering via the Crossref "
"API on 2026-05-21: the journal began at volume 1 in 2015; articles "
"published in 2024 carry volume 10; articles published in 2025 carry "
"volume 11."
),
"finding": (
"The disputed citation pairs '(2024)' with 'volume 11'. European Urology "
"Focus volume 11 corresponds to publication year 2025, and 2024 "
"corresponds to volume 10. No real article in this journal can satisfy "
"both coordinates simultaneously -- the citation is internally "
"inconsistent. This is independent corroboration that the citation does "
"not describe a real paper; it does not break the proof."
),
"breaks_proof": False,
},
{
"question": (
"Could a real paper by these authors on this topic exist under different "
"citation coordinates, making the claim too strong?"
),
"verification_performed": (
"A.C. Goh and I.S. Gill are real urologic surgeons who have co-published. "
"Searched their joint publication record on PubMed on 2026-05-21 "
"('Goh AC[Author] AND Gill IS[Author] AND Wallace')."
),
"finding": (
"The only Goh-AC + Gill-IS record involving 'Wallace' in PubMed is PMID "
"25016136, 'Robotic intracorporeal orthotopic neobladder during radical "
"cystectomy in 132 patients', J Urol 2014;192:1734-40 -- a different "
"paper with a different title in a different journal and year. No paper "
"titled 'Wallace anastomosis in complex dissections' by these authors "
"exists in any index. The disputed citation recombines real authors, a "
"real journal, and a real surgical technique into a reference whose "
"target does not exist."
),
"breaks_proof": False,
},
]
# ---------------------------------------------------------------------------
# 9. VERDICT AND STRUCTURED OUTPUT
# ---------------------------------------------------------------------------
if __name__ == "__main__":
is_absence = CLAIM_FORMAL.get("proof_direction") == "absence"
any_breaks = any(ac.get("breaks_proof") for ac in adversarial_checks)
any_unverified = any(
cr["status"] != "verified" for cr in citation_results.values()
)
if any_breaks:
base_verdict = "UNDETERMINED"
elif claim_holds:
if is_absence:
base_verdict = "SUPPORTED"
elif CLAIM_FORMAL.get("proof_direction") == "disprove":
base_verdict = "DISPROVED"
else:
base_verdict = "PROVED"
else:
base_verdict = "UNDETERMINED"
verdict = apply_verdict_qualifier(base_verdict, any_unverified)
builder = ProofSummaryBuilder(CLAIM_NATURAL, CLAIM_FORMAL)
for fid, info in FACT_REGISTRY.items():
if fid.startswith("S"):
sr_key = info["key"]
entry = search_registry[sr_key]
sr = search_results.get(sr_key, {})
builder.add_search_fact(
fid,
label=info["label"],
database=entry["database"],
url=entry["url"],
search_url=entry["search_url"],
query_terms=", ".join(entry["query_terms"]),
date_range=entry["date_range"],
result_count=entry["result_count"],
source_name=entry["source_name"],
)
builder.set_extraction(
fid,
value=sr.get("status", "unknown"),
value_in_quote=sr.get("status") == "accessible",
quote_snippet=f"result_count={entry['result_count']}",
)
builder.add_computed_fact(
"A1",
label="Unique accessible databases with null results",
method=f"count of unique accessible databases with result_count == 0 = {n_null_verified}",
result=n_null_verified,
depends_on=[fid for fid in FACT_REGISTRY if fid.startswith("S")],
)
builder.add_cross_check(
description=(
"Systematic searches of four independent scholarly indexes for any "
"record of the disputed article"
),
fact_ids=[fid for fid in FACT_REGISTRY if fid.startswith("S")],
n_databases_searched=len(search_registry),
n_null_verified=n_null_verified,
n_reviewed=n_reviewed,
databases={
key: {
"database": entry["database"],
"result_count": entry["result_count"],
"status": search_results[key]["status"],
}
for key, entry in search_registry.items()
},
independence_note=(
"PubMed (NLM), Europe PMC (EMBL-EBI), OpenAlex (OurResearch) and "
"Crossref (DOI registration agency) maintain separate indexes with "
"independent ingestion pipelines; all four would index a genuine 2024 "
"or 2025 European Urology Focus article."
),
agreement=claim_holds,
)
for ac in adversarial_checks:
builder.add_adversarial_check(
question=ac["question"],
verification_performed=ac["verification_performed"],
finding=ac["finding"],
breaks_proof=ac["breaks_proof"],
)
builder.set_verdict(base_verdict, any_unverified=any_unverified)
builder.set_key_results(
n_databases_searched=len(search_registry),
n_null_verified=n_null_verified,
n_reviewed=n_reviewed,
n_corroborating=n_corroborating,
search_threshold=CLAIM_FORMAL["search_threshold"],
corroboration_threshold=CLAIM_FORMAL["corroboration_threshold"],
searches_met=searches_met,
corroboration_met=corroboration_met,
claim_holds=claim_holds,
)
print()
print(f"VERDICT: {verdict}")
print()
builder.emit()
Re-execute this proof
The verdict above is cached from when this proof was minted. To re-run the exact
proof.py shown in "View proof source" and see the verdict recomputed live,
launch it in your browser — no install required.
Re-execute the exact bytes deposited at Zenodo.
Re-execute in Binder runs in your browser · ~60s · no installFirst run takes longer while Binder builds the container image; subsequent runs are cached.
machine-readable formats
Downloads & raw data
Embed this proof
Cite this proof in your wiki, docs, or README:
Preview:
found this useful? ★ star on github