Title. An Independent Reproduction and Four Extensions of the MUB(6) Fourth-Vector Feasibility Wall Abstract. We present a companion note that cites N. Erlwein’s exact fourth-vector feasibility wall for a canonical mutually unbiased product triple in dimension six (Zenodo 20682233; theorem W = (88 + 3√6)/100). We do not redistribute the upstream software bundle. Independently, we (A) maintain a pure-Rust exact verification surface; (B) raise a d=10 closed-form hunt to a 460-decimal-place stationarity anchor with a widened PSLQ menu (no relation found); (C) run a full Cl(2)×Cl(5) single-qudit Clifford census at d=10, finding a single antiunitary Z/2 real structure; and (D) issue exact rational finite-cover exclusion certificates on a specified cell of the gauge-fixed candidate 5-torus. MUB(6)=3 and MUB(10) remain open. Local certificates mint no authority. Why a researcher should care. The note strengthens a rare exact, machine-checkable obstruction artifact in d=6 quantum information with a second language (Rust), higher-precision d=10 evidence, and independently checkable finite covers—while keeping claim boundaries explicit. What this does not claim. Not MUB(6)=3; not MUB(10); not a closed form at d=10; not joint authorship of Erlwein’s wall; not a global moduli theorem. Reproduction. cd crate && cargo test -j 1cargo run --release --bin mub_cover -- --region quadrant DOI. Pending human mint. Upstream wall: 10.5281/zenodo.20682233.
Title. An Independent Reproduction and Four Extensions of the MUB(6) Fourth-Vector Feasibility Wall Abstract. We present a companion note that cites N. Erlwein’s exact fourth-vector feasibility wall for a canonical mutually unbiased product triple in dimension six (Zenodo 20682233; theorem W = (88 + 3√6)/100). We do not redistribute the upstream software bundle. Independently, we (A) maintain a pure-Rust exact verification surface; (B) raise a d=10 closed-form hunt to a 460-decimal-place stationarity anchor with a widened PSLQ menu (no relation found); (C) run a full Cl(2)×Cl(5) single-qudit Clifford census at d=10, finding a single antiunitary Z/2 real structure; and (D) issue exact rational finite-cover exclusion certificates on a specified cell of the gauge-fixed candidate 5-torus. MUB(6)=3 and MUB(10) remain open. Local certificates mint no authority. Why a researcher should care. The note strengthens a rare exact, machine-checkable obstruction artifact in d=6 quantum information with a second language (Rust), higher-precision d=10 evidence, and independently checkable finite covers—while keeping claim boundaries explicit. What this does not claim. Not MUB(6)=3; not MUB(10); not a closed form at d=10; not joint authorship of Erlwein’s wall; not a global moduli theorem. Reproduction. cd crate && cargo test -j 1cargo run --release --bin mub_cover -- --region quadrant DOI. Pending human mint. Upstream wall: 10.5281/zenodo.20682233.
For the canonical product MUB triple {Z₂ ⊗ Z₃, X₂ ⊗ Q₀, Y₂ ⊗ Q₁} in dimension six, known to admit no vector unbiased to all three bases, we prove an exact two-sided theorem for the projector-space feasibility functional f, where f(v) = 1 would characterize a candidate fourth unbiased vector. We show that the global maximum of f is W = (88 + 3√6) / 100 ≈ 0.9534846923. The bound is attained by an explicit algebraic unit vector, verified entirely in exact arithmetic over the field Q(ζ₂₄, √5). Its symmetry orbit contains 72 distinct maximizing rays. The matching global upper bound f ≤ W is established via an exact positive-semidefinite certificate at the level-2 Veronese lift. The certificate consists of a symmetric matrix over Q(√2, √3), whose polynomial identity and positivity are machine-verified in exact arithmetic and closed deterministically under the triple's 432-element symmetry group. No randomized computation or floating-point arithmetic appears anywhere in the proof chain. We further prove, via exact separating functionals, that degree-4 and degree-6 sum-of-squares certificates do not exist. In this precise sense, the lift level employed is minimal and necessary. Companion results include: • an exact product-vector ceiling for aligned product triples; • the exact wall value for the second known triple; • a complete Weyl-board census in dimension six, together with a Lean 4 kernel-verified combinatorial layer. These results completely characterize the pinned canonical triple. They do not resolve the MUB(6) problem, which remains open. The deposit contains two files: (1) the manuscript (PDF); (2) a complete verification bundle (ZIP; 91 files) containing all computational modules, tests, evidence receipts, execution logs, a SHA-256 manifest, and a minimal independent verifier (verify_global_certificate.py). The verifier is implemented in standard-library-only Python, shares no code with the certificate-construction pipeline, loads the stored exact certificate matrix, and independently re-establishes both directions of the global bound in approximately 150 seconds. Reproduction is available via: make verify-global Code is released under the Apache License 2.0 (with SPDX headers throughout the bundle). The manuscript text is released under CC BY 4.0. This research made extensive use of AI systems for conjecture generation, computation, proof drafting, and adversarial review. However, no mathematical claim depends on the correctness of any AI system. Every reported result is verified by exact rational arithmetic, exact interval arithmetic, or the Lean 4 kernel, and all verification artifacts are included in the deposit.
Which pure states give uniform outcomes in several mutually unbiased measurements, and when can they form another measurement basis? We distinguish common unbiased states, their orthonormal completion, and further extension. For a displayed phase-deformed Fourier pair in dimension 2m, a clock symmetry and skew antiunitary complete every prescribed common unbiased state to an explicit orthonormal basis. In dimension six, an amplitude-profile obstruction proves strong unextendibility of a given mutually unbiased triple when its original third-basis rays are invariant under the ternary clock. We give an exact nonproduct example and an application to a companion whose columns are localized at single Fourier frequencies. For every exact Hadamard matrix in a specified closed entrywise neighborhood of a fixed reference matrix, the coordinate and Hadamard bases have exactly 48 common unbiased rays but no third measurement basis, with a quantitative lower bound on the squared Gram defect of every six-column candidate.
We also study auxiliary complex equations for common states, retaining algebraic multiplicities. For a flat unitary of order six with all 3×3 minors nonzero, the projective ray scheme is finite; each singular two-minor contributes two reduced isolated boundary points, and the affine coordinate algebra is finite-dimensional over C. In every order, a critical-algebra identity preserves multiplicities; in dimension six it gives finiteness for a fixed phase fibre. Specialization over a discrete valuation ring controls complete reciprocal-orthogonal collections. A nonphysical Tao/Potts collection separates algebraic from physical solutions. These results do not determine the global maximum number of mutually unbiased bases or classify all triples.
Paper 1 of 11 — A General Theory of Answerability The eleven-paper TUS OS mathematical research programme Abstract This paper establishes an exact tetrahedral qubit-state geometry within the deterministic six-bit construction underlying the TUS OS Triad. For every lawful six-bit anchor A, the full-state-space maximin construction selects companions B,C such that the resulting triple has exact pairwise Hamming separation (4,4,4). Every such triple has a unique equidistant completion in the same six-bit state space, given by D = A ⊕ B ⊕ C. Under the normalised sign embedding, the four completed states have unit norm, pairwise inner product −1/3, zero centroid and rank three. They therefore form the vertices of a regular tetrahedron. The paper constructs an exact isometric representation of this geometry as four qubit Bloch vectors forming a tetrahedral symmetric informationally complete structure, while affine centring and common renormalisation of the original three-state face yield exact qubit-trine geometry. The analytical construction is verified exhaustively over the complete finite state space. The census covers all 64 six-bit anchors, 249,984 ordered anchor-conditioned candidate pairs, 41,664 unordered triples, 960 mutual-distance-four triples, and 240 completed four-state sets. The same geometric recovery is demonstrated in two frozen public TUS receipt packages. The result separates the mathematical completion from the protocol object. Only the three states (A,B,C) are emitted as active Triad starts; the fourth state (D) is a uniquely determined mathematical completion and does not become an additional receipt-bearing protocol member. The tetrahedral and trine constructions therefore provide exact qubit-geometric representations of an already-fixed finite classical structure rather than additional states or operations in the native TUS OS protocol. The claim boundary is explicit. The paper does not claim that TUS OS physically prepares qubits, performs SIC or trine measurements, exhibits contextuality or other nonclassical behaviour, or obtains quantum computational advantage. Its result is an exact finite geometric correspondence and protocol linkage between the completed six-bit Triad structure and canonical qubit tetrahedral and centred-face trine geometry. Supporting General Theory Programme This paper is Paper 1 and the opening theorem paper in the TUS OS quantum-operational and Answerability research programme. It proves that the canonical six-bit TUS OS Triad has exact (4,4,4) Hamming geometry, a unique XOR completion, regular-tetrahedral geometry, an exact qubit-SIC representation, and centred-face trine geometry. Paper 2 develops the exact operational calculus and full-carrier qubit prepare–measure representation. Paper 3 extends the result to the complete relational Atlas and exact global static quantum dimension. Paper 4 develops the complete-future, orthogonality, process, LANDING/GUIDANCE, and native Triadic synthesis theory. Paper 5 introduces the Anchored Analog Quantum System framework, while Papers 6–7 generalise the contract-relative resource and operational-observability structure. Papers 8–9 then develop generic Answerability theory, Paper 10 proves the complete protected and executable realisation of TUS OS in the Answerability Calculus, and Paper 11 closes the programme with A General Theory of Answerability, establishing Structural Identity, Recognition, the canonical mandatory protected core, and lawful Realisation Freedom. Paper 1 therefore provides the mathematical starting point for the complete programme. Paper 1 — Canonical Tetrahedral Qubit-State Geometry in the TUS OS Triad XOR Completion, Receipt Verification and the Qubit-Geometric Semantic WitnessEstablishes the canonical tetrahedral geometry, unique XOR completion and exact qubit-SIC representation. The canonical maximin construction yields a unique same-space completion whose normalised sign embedding forms a regular tetrahedron, while the centred and commonly renormalised emitted face has exact qubit-trine geometry. The emitted three-state face itself is not asserted to be a trine before that affine centring and normalisation. Paper 2 — The TUS OS Operational CalculusClassical Construction of Exact Qubit Prepare–Measure Behaviour from a Receipt-Custodied Engine ArchitectureExtends the Paper 1 geometry to exact full-carrier qubit prepare–measure behaviour from the deterministic classical engine under the declared Coordinate-Incidence Operational Harness. For each lawful foundation, the 64 six-bit carriers map to exactly 27 anchor-relative qubit preparations, while the separately declared face Harness gives the exact trine table. Paper 3 — From Finite Relational Structure to Qubit Operational FormAmbient Foundations, Canonical Subatlas, Exact Global Quantum Dimension, GUIDANCE Witness, Sequential Closure and Global Representation in TUS OSExtends the local construction to the completed-foundation family and canonical TUS OS subatlas, establishes exact carrier-reconstruction structure, proves that the repeated-common-effect static Atlas has exact minimum complex Hilbert dimension 4, and establishes deterministic predictive-state minimum 64 for the frozen complete principal future language. Paper 4 — Technical Volume I — Formal Foundations and the Complete-Future CorpusNative Contract, Statistical Discrimination and the Invariant Probability ModuleFixes the formal native domain, complete principal terminal future-experiment language and one-common-word experiment class; establishes complete statistical separation of distinct carrier pairs, exact parity-resolved discrimination results and complement reachability; and proves that the rational invariant probability module has dimension 33. Paper 4 — Technical Volume II — Orthogonality, Process Closure and Native Triadic SynthesisEstablishes universal complement-support orthogonality and its propagation under exact common-CPTP dynamics, yielding the certified same-parity support graph and the bound 32 ≤ d_CPTP^min ≤ 64, with cross-parity forcing and the exact state-only common-CPTP minimum remaining unresolved. It further establishes recovery-complete LANDING and GUIDANCE results, exact 64-dimensional selected-line instrument/readout minima at their declared contracts, an exact classical–quantum hybrid construction, and the native structural/predictive quotient correspondence. Paper 5 — TUS OS as an Anchored Analog Quantum SystemNative Witnesses, Predictive Synthesis, and Access-Contract Resource SeparationDefines Analog Quantum Views and Anchored Analog Quantum Systems, proves that TUS OS is a proper Anchored Analog Quantum System on its 64-input abstract canonical corpus, elevates the inherited structural/predictive correspondence into the Predictive Synthesis Identity Theorem, organises the inherited exact quantum-operational results through a typed access-contract resource law, and composes the recognition, predictive, resource and downstream-conservation results into the TUS OS Anchored Analog Quantum System Theorem. Paper 6 — Contract-Relative Quantum Realisations of Classical ProcessesPredictive Compression, Vanishing Worst-Case Causal-State Transparency, and Finite-Dimensional BreakdownGeneralises the access-dependent resource phenomenon beyond the TUS-specific discovery corpus by formalising the contract-relative achievable-resource object (S,C,𝔐,ε) ⟼ Ach(S,C;𝔐,ε), and establishes three exact contract-relative regimes: strict finite separation, unbounded finite separation and finite-capacity breakdown. These are instantiated respectively by the TUS OS 4→64 separation, the periodically modulated decay 2→N exact prediction-to-transparency separation, and dual-Poisson finite-capacity breakdown for every positive uniform worst-case transparency threshold. Paper 7 — Operational Observability and Contract-Induced Resource Transitions in Quantum RealisabilityStructural Classification, Family Scaling, and Finite-Resource BreakdownDevelops a structural classification theory for contract-induced representation-resource transitions, introducing the Contract Distinction System (CDS), CRC cofinal/refinement equivalence, and Certified Observability Transport Theory (COTT). It separates internal divergence from family divergence, classifies baseline-feasible strengthenings as resource-neutral, strict finite, finite-resource breakdown, or UNRESOLVED, and proves exact and asymptotic witnesses including an interface-induced 2→3 separation, the TUS OS 4→64 transition, incrementally unbounded finite separation for periodically modulated decay processes, and finite-resource breakdown for positive-threshold dual-Poisson transparency. Paper 8 — The Resource Geometry of Answerable InferenceIrreducible Answerability Structure, Minimal Sufficient Cores, and Certified Inference-Resource BoundariesDevelops the resource geometry of answerable inference. It formalises lawful-discharge semantics, source-level inferential obligations, answerability-sufficient reductions and irreducible sufficient cores, while keeping semantic structure, certified lower bounds and operational feasibility independently constituted. Gate E establishes a local answerability-to-resource threshold result; globally, exact closure identifies the Pareto-minimal inference-resource boundary. On the generated exact branch, L = ↑F, and under well-partial-order conditions the resulting lower-resource geometry has a unique finite canonical antichain normal form. Paper 9 — The Answerability CalculusLawful Reduction, Contract–Resource Representation, Composition and ActivationDevelops a general mathematical calculus of Answerability as a constituted, typed relation. Its Base Theorem states that no terminal proposition counts as an answer unless it lawfully discharges the independently constituted contract. The paper develops lawful reduction, contract–resource geometry, extremal representation, repai
Unrefereed candidate excluding the specified closed two-circulant Szollosi family from MUB quadruplets in complex dimension six. The Fourier-family result re-proves prior work. The unrestricted dimension-six maximum remains conditional on MMVW Conjecture 2. The package separates an untrusted hull generator from an interval and graph checker; canonical half-open ownership repairs boundary coverage, and input-bound clean replay prevents stale cache acceptance. No end-to-end formal verification, unaffiliated reproduction or external human peer review is claimed. See the replay receipt for exact measured scope. Original prose and data CC0; original code MIT; third-party and review material retain their terms.
Paper 3 of 11 — A General Theory of Answerability The eleven-paper TUS OS mathematical research programme Abstract This paper develops an exact finite local-to-global analysis of the six-dimensional Hamming-cube foundation Atlas underlying the TUS OS construction. Every admissible completed foundation carries the same exact local qubit prepare–measure representation, while the complete repeated-common-effect Atlas has exact minimum complex Hilbert dimension four. The paper classifies the full ambient family of completed four-state foundations in the six-dimensional Hamming cube. Every foundation is uniquely an affine coset associated with a perfect matching of the six coordinates. There are exactly 240 unordered foundations and 5,760 ordered codebooks. Every foundation induces the same exact 27-class tetrahedral-SIC qubit operational quotient, with carrier-fibre profile 1⁸, 2¹², 4⁶, 8¹ and the corresponding Bloch-radius structure of eight pure states, twelve states of radius √(2/3), six states of radius 1/√3, and one maximally mixed state. Each ambient chart reduces losslessly to a signed perfect matching. The chart-coloured union of two matchings obeys an exact component-parity collision law, yielding the complete seven-value image spectrum over all 28,680 ambient foundation pairs. Exactly 10,800 pairs jointly reconstruct the full 64-state carrier, giving an ambient mathematical chart-cover number of two. The frozen TUS selector defines a canonical subatlas of 36 distinct foundations and 64 anchor-indexed chart instances across nine matching classes. Its selected-foundation reconstruction graph is bipartite and eight-regular with 144 edges, while selector multiplicity yields exactly 400 reconstructing pairs among the 2,016 canonical chart-instance pairs. Only this canonical subatlas inherits the native LANDING and GUIDANCE structure. At the sequential level, all 384 active map/chart descent tests fail: no active LANDING map descends to a state-only transformation on a fixed 27-class local chart quotient. Under the complete principal future language, every canonical chart refines to all 64 deterministic predictive states, with maximum separating depth two. The subordinate GUIDANCE witness is also classified: its endpoint map has image size 34, eight two-cycle attractors and maximum transient depth five, while the additional GUIDANCE-selected chart raises principal path reconstruction from 138/192 contexts to 169/192. The paper then establishes the exact global static common-effect Hilbert dimension. Although every individual foundation admits an exact qubit representation, no unrestricted qutrit state/common-effect family can reproduce all 4,096 Atlas probabilities while simultaneously satisfying all 240 overlapping foundation POVM identities. Together with an explicit chart-independent dimension-four construction, this proves d_q^atlas = 4 for the complete static Atlas. The attaining construction uses two declared qubit sectors; unrestricted uniqueness or rigidity of minimum representations is not claimed. The result therefore exhibits a precise local-to-global separation: exact qubit prepare–measure form exists on every individual foundation, but an exact chart-independent repeated-common-effect representation of the complete Atlas requires complex Hilbert dimension four, while the complete deterministic future language preserves all 64 predictive identities. Local operational state, global relational state and deterministic predictive state are consequently distinct mathematical structures. The paper explicitly keeps these distinct from the still-unresolved whole-position process state. The scope boundary is explicit. The paper does not establish a physical quantum carrier, operational access to all 240 ambient foundations, LANDING as a quantum channel, GUIDANCE as a quantum observable, endpoint channel or instrument, contextuality, nonlocality, quantum advantage, unrestricted rigidity of minimum representations, or whole-position process synthesis. Its conclusions are exact at the static Atlas, canonical-chart and deterministic predictive scopes defined in the manuscript. Supporting General Theory Programme This paper is Paper 3 in the TUS OS quantum-operational and Answerability research programme. It extends the results of Papers 1–2 from the canonical local geometry and exact qubit prepare–measure behaviour to the complete finite relational Atlas. It classifies the full family of admissible foundations, proves that every local chart carries the same exact 27-class qubit operational quotient, identifies the canonical TUS subatlas, and shows that the complete native future language refines those local quotients back to all 64 deterministic predictive states. Its principal global result is that the complete common-effect Atlas has exact minimum quantum dimension d=4, while remaining distinct from the larger 64-state predictive structure and from later process-level dynamics. The paper also classifies the subordinate GUIDANCE witness and its finite reconstruction contribution without promoting it into a channel or instrument. The wider programme then develops complete-future and process closure in Paper 4, the Anchored Analog Quantum System framework in Paper 5, contract-relative resource and operational-observability theory in Papers 6–7, generic Answerability theory in Papers 8–9, complete TUS OS formal and executable realisation in Paper 10, and culminates in Paper 11 with A General Theory of Answerability. Paper 1 — Canonical Tetrahedral Qubit-State Geometry in the TUS OS TriadXOR Completion, Receipt Verification and the Qubit-Geometric Semantic WitnessEstablishes the canonical tetrahedral geometry, unique XOR completion, exact qubit-SIC representation and centred-face trine geometry. Paper 2 — The TUS OS Operational CalculusClassical Construction of Exact Qubit Prepare–Measure Behaviour from a Receipt-Custodied Engine ArchitectureEstablishes exact full-carrier qubit prepare–measure behaviour from the deterministic classical engine under the declared Coordinate-Incidence Operational Harness. For each lawful foundation, the 64 six-bit carriers map to exactly 27 anchor-relative qubit preparations under one foundation-defined tetrahedral-SIC Harness, while the separately declared face Harness gives the exact trine table. Paper 3 — From Finite Relational Structure to Qubit Operational FormAmbient Foundations, Canonical Subatlas, Exact Global Quantum Dimension, GUIDANCE Witness, Sequential Closure and Global Representation in TUS OSExtends the local prepare–measure construction to the complete ambient family of 240 completed foundations and the canonical TUS OS subatlas. Every completed foundation has the same 27-class qubit operational quotient; pair relations between charts provide exact carrier-reconstruction structure; the complete repeated-common-effect static Atlas has exact minimum complex Hilbert dimension 4; and the frozen complete principal future language has deterministic predictive-state minimum 64. The dimension-4 result is a static representation theorem and does not by itself supply common quantum process dynamics. Paper 4 — Technical Volume I — Formal Foundations and the Complete-Future CorpusNative Contract, Statistical Discrimination and the Invariant Probability ModuleFixes the formal native domain, complete principal terminal future-experiment language and one-common-word experiment class; establishes complete statistical separation of distinct carrier pairs, exact parity-resolved discrimination results and complement reachability; and proves that the rational invariant probability module has dimension 33. Paper 4 — Technical Volume II — Orthogonality, Process Closure and Native Triadic SynthesisEstablishes universal complement-support orthogonality and its propagation under exact common-CPTP dynamics, yielding the certified same-parity support graph and the bound 32 ≤ d_CPTP^min ≤ 64, with cross-parity forcing and the exact state-only common-CPTP minimum remaining unresolved. It further establishes recovery-complete LANDING and GUIDANCE results, exact 64-dimensional selected-line instrument/readout minima at their declared contracts, an exact classical–quantum hybrid construction, and the native structural/predictive quotient correspondence. Paper 5 — TUS OS as an Anchored Analog Quantum SystemNative Witnesses, Predictive Synthesis, and Access-Contract Resource SeparationDefines Analog Quantum Views and Anchored Analog Quantum Systems, proves that TUS OS is a proper Anchored Analog Quantum System on its 64-input abstract canonical corpus, elevates the inherited structural/predictive correspondence into the Predictive Synthesis Identity Theorem, organises the inherited exact quantum-operational results through a typed access-contract resource law, and composes the recognition, predictive, resource and downstream-conservation results into the TUS OS Anchored Analog Quantum System Theorem. Paper 6 — Contract-Relative Quantum Realisations of Classical ProcessesPredictive Compression, Vanishing Worst-Case Causal-State Transparency, and Finite-Dimensional BreakdownExtends the programme beyond the TUS-specific discovery corpus by formalising the contract-relative achievable-resource object (S,C,𝔐,ε) ⟼ Ach(S,C;𝔐,ε), and establishes three exact contract-relative regimes: strict finite separation, unbounded finite separation and finite-capacity breakdown. These are instantiated respectively by the TUS OS 4→64 separation, the periodically modulated decay 2→N exact prediction-to-transparency separation, and dual-Poisson finite-capacity breakdown for every positive uniform worst-case transparency threshold. Paper 7 — Operational Observability and Contract-Induced Resource Transitions in Quantum RealisabilityStructural Classification, Family Scaling, and Finite-Resource BreakdownDevelops a structural classification
Unrefereed candidate, Anonymous, version 0.2.0-candidate. A finite integer certificate and written analytic argument establish a necessary leakage inequality on the full classical real binary RBM(4,3) visible closure, an eight-point obstruction to universality, a strictly positive excluded law, and non-sharp total-variation lower bounds. A contrasting exact construction represents every distribution on the specified parity-plus-one support. At least four hidden units are necessary; four-hidden sufficiency, smallest excluded support, complete classification, practical training penalties and historical priority are not established. The archive includes solver-free standard-library checkers, exact data, manuscript and PDF, normal/optimized hostile regression controls, source comparison, and one five-role coordinated AI internal editorial round. Producer checks and coordinated reconstruction are not unaffiliated reproduction, human specialist endorsement, journal peer review, or formal verification. The supplied external AI review reports a separate reconstruction but its linked audit ZIP was not retrieved. Original prose and data are CC0; code is MIT; upstream terms are preserved in LICENSES.md. The frozen editorial submission is included separately for audit and is superseded by the final release archive.