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The Projective Hierarchy of Computation: Classical, Clifford, and Magic as Shadows of the Meld

Ian Richard C Buckley

Published Jul 6, 2026• 0 citations
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Abstract

Establishes the H^k complexity ladder as a projective hierarchy: H0 (classical/tropical) and H1 (Clifford/stabiliser) are projective shadows of H2 (magic/metaplectic). The Meld — the H2 completion of the ISA — projects onto Origami (H0+H1 shadow) and Forge (H1 shadow) in the same way that a 3D object projects onto 2D shadows. Derives the Palmer Invariant Space-time conjecture as the fixed-point condition of Penrose objective reduction within this framework.

DOI
10.5281/zenodo.21219706

Related papers

The Meld ISA: Complex-MGE, Quantum Algorithm Discovery, and the T-Gate as Octonion Obstruction

Ian Richard C Buckley

PENDING QUALITY AUDIT (2026-08). The file is restricted while this record is reviewed as part of a systematic audit of the author's corpus. It has not yet been assessed. Metadata and DOI remain public, and access can be requested. We complete the TRS trilogy — Origami ($\beta\to\infty$, tropical, classical), Forge ($0<\beta<\infty$, real, statistical), Meld ($\beta=it$, complex, quantum) — by showing that the Meld ISA is the quantum circuit model expressed in the TRS semiring language. Three results follow. Result 1 (ISA completeness). The Clifford group equals the Meld ISA without the BIND opcode. Universal quantum computation equals Meld plus BIND. The T-gate $T = \mathrm{diag}(1,, e^{i\pi/4})$ is the BIND opcode at $j=\tfrac{1}{2}$ — the Fano associator obstruction of Paper 407, applied to qubit representations. The magic-typing classification of Papers 365/366 maps exactly onto the 731-ISA opcode hierarchy: Clifford gates occupy Fano-line orbits (SPLIT/FLIP/TWIST at Clifford angles); the T-gate occupies the non-collinear Fano triple (BIND). Result 2 (Quantum algorithm factory). Every classical algorithm of the form $\arg\max_{g\in G} f(g)$ over an abelian group $G$ has a $\mathbb{C}$-MGE quantum counterpart $\mathbb{C}\text{-MGE}(f) = \mathrm{SPLIT}_G \cdot \mathrm{FLIP}(f) \cdot \mathrm{SPLAT}$, giving exponential speedup via quantum Fourier sampling whenever $G$ is abelian and $f$ has a hidden subgroup concentrating Fourier mass. Shor's algorithm decomposes into three ISA layers: Layer 1 (Origami — classical modular exponentiation), Layer 2 (Meld — QFT as SPLIT-TWIST-FLIP cascade), Layer 3 (Origami — measurement as tropical projection). "Frozen-Shor" (Origami ISA, $\beta\to\infty$) recovers classical exhaustive search at cost $O(N)$. "Warm-Shor" (Forge ISA, real $\beta$) gives Grover-like $O(\sqrt{N})$ thermal concentration. Full Shor (Meld, $\beta=it$) achieves $O(\log N)$ via destructive interference — a resource unavailable in either real ISA. New algorithm candidates follow by identifying the symmetry group of the target problem: equivariant ML, quantum persistent homology (Lloyd-Garnerone-Zanardi 2016), and Boson Sampling (Aaronson-Arkhipov 2011) all fit the five-step factory template. Result 3 (ML-KEM structural no-go). ML-KEM (Module-LWE) is immune because LWE noise exponentially suppresses every Fourier component: $\mathbb{E}{\mathbf{e}\sim D\sigma}[e^{i\langle\xi,\mathbf{e}\rangle}] = e^{-|\xi|^2\sigma^2/2}$. No Fourier peak exists; SPLAT cannot extract a period. The deeper reason is that worst-case LWE reduces to the dihedral hidden subgroup problem (Regev 2002) — a non-abelian problem for which no efficient Meld program is known. Breaking ML-KEM would require a BIND opcode capable of distinguishing dihedral cosets, a capability not established for the current 731-Meld. The $H^k$ complexity ladder (Paper 420) is realised by the trilogy: $H^0$ (tree) = Origami, $H^1$ (loop) = Forge/BPP, $H^2$ (surface) = Meld/BQP. The T-gate is the $H^2$ generator that lifts computation off the stabiliser submanifold into the curved interior of the Fisher information metric. Series: Paper 258 (Origami ISA) → Paper 419 (Forge ISA) → Paper 443 ($\oplus_\beta$ semiring, six pairs) → Paper 453 (multi-sector Forge) → Paper 454 (this paper — Meld ISA, trilogy complete). Related identifiers (Cites) Paper 258 Origami ISA: doi:10.5281/zenodo.19916429 Paper 419 Forge ISA: doi:10.5281/zenodo.20694527 Paper 443 ⊕_β semiring: doi:10.5281/zenodo.20752384 Paper 407 Associamancy: doi:10.5281/zenodo.20702223 Paper 365 Fano Magic Factory: doi:10.5281/zenodo.20541583 Paper 366 CS Magic Composition: doi:10.5281/zenodo.20541665 Paper 445 Kitaev anyons: doi:10.5281/zenodo.20752352 Paper 453 Multi-sector Forge: doi:10.5281/zenodo.20773423 Paper 420 H^k complexity ladder: doi:10.5281/zenodo.20773526

•Jun 20, 2026•0 citations

Information Geometry as the H^k Ladder: Fisher Metrics, Alpha-Connections, and Quantum Holonomy in the Origami ISA

Ian Richard C Buckley

Maps the full programme of information geometry onto the H^k ISA ladder. H0 corresponds to flat exponential families and tropical likelihood (A(theta) as tropical potential); H1 to Amari's alpha-connection and TWIST monodromy; H2 to Uhlmann holonomy and BIND. The EM algorithm is a SPLIT/SPLAT cycle; the beta* snap is the maximum Fisher information threshold. Provides a unified ISA syntax for classical and quantum information geometry.

•Jul 8, 2026•0 citations

The Three Forms of the Maslov-Gibbs Einsum: Tropical, Clifford, and Metaplectic

Ian Richard C Buckley

Shows that the Maslov-Gibbs Einsum (MGE) takes three canonical forms corresponding to the H0/H1/H2 complexity tiers: tropical (min-plus at beta = infinity), Clifford/geometric-Kitaev (at beta = beta*), and metaplectic/Maslov-index (at beta = 0 or imaginary). Establishes the Maslov duality theorem connecting H0 and H2 forms via Legendre transform. Introduces the Penrose empire analogy for H2 non-locality and identifies an H3 frontier.

•Jul 6, 2026•0 citations

Clifford Hierarchy Stabilizer Codes: Transversal Non-Clifford Gates and Magic

Ryohei Kobayashi, Guanyu Zhu, Po-Shen Hsin

A fundamental problem in fault-tolerant quantum computation is the tradeoff between universality and dimensionality, exemplified by the the Bravyi-König bound for $n$-dimensional topological stabilizer codes. In this work, we extend topological Pauli stabilizer codes to a broad class of $n$-dimensional Clifford hierarchy stabilizer codes. These codes correspond to the $(n+1)$D Dijkgraaf-Witten gauge theories with non-Abelian topological order. We construct transversal non-Clifford gates through automorphism symmetries represented by cup products. In 2D, we obtain the first transversal non-Clifford logical gates including T and CS for Clifford stabilizer codes, using the automorphism of the twisted $\mathbb{Z}_2^3$ gauge theory (equivalent to $\mathbb{D}_4$ topological order). We also combine it with the just-in-time decoder to fault-tolerantly prepare the logical T magic state in $O(d)$ rounds via code switching. In 3D, we construct a transversal logical $\sqrt{\text{T}}$ gate in a non-Clifford stabilizer code at the third level of the Clifford hierarchy, located on a tetrahedron corresponding to a twisted $\mathbb{Z}_2^4$ gauge theory. Our constructions surpass the Bravyi-König bound by achieving the logical gates in the $(n+1)$-th level of Clifford hierarchy in $n$ spatial dimension.

quant-pharXiv:2511.02900•Physical Review Letters•Nov 6, 2025•1 citation

The Three Forms of the Maslov-Gibbs Einsum: H⁰ Tropical, H¹ Clifford, H² Metaplectic

Ian Richard C Buckley

The Maslov-Gibbs Einsum (MGE) is not a single algorithm but a family of tensor contraction schemes indexed by the cohomological level $H^k$ of the physical system. This paper identifies three distinct forms: $H^0$ MGE (classical/tropical): contraction over the min-plus tropical semiring, corresponding to Maslov dequantisation ($\hbar \to 0$). Finds the dominant classical path; computational class P. $H^1$ MGE (Clifford/stabiliser): contraction over the stabiliser calculus of the Clifford group $\mathsf{C}_2$. Captures quantum interference within the stabiliser sector. Classically simulable in polynomial time by the Gottesman-Knill theorem, but exponentially more expressive than $H^0$: captures non-local correlations, entanglement, and quantum error correction. $H^2$ MGE (metaplectic/magic): contraction with Maslov index phase corrections. Each gate composition $g \circ h$ acquires a $\mathbb{Z}_2$ phase factor $(-1)^{\tau(L, gL, ghL)}$ from the Maslov index of three Lagrangian subspaces. The TWIST opcode in the Origami ISA counts how many times this correction fires; TWIST $> 0$ is necessary and sufficient for $H^2$ MGE. Computational class BQP-hard. The central observation is that Viktor Maslov named both ends of this ladder: Maslov dequantisation ($H^0$, 1990s) and the Maslov index ($H^2$, 1965) are not coincidentally related — they are the two limits of the same quantisation programme, with the Clifford/Berry-phase level $H^1$ interpolating between them. The name "Maslov-Gibbs Einsum" was more prophetic than intended: Maslov's index governs the $H^2$ correction as well as the $H^0$ tropical limit. The Origami ISA compiler selects the MGE form automatically: TWIST $= 0$ implies $H^1$ MGE suffices; TWIST $> 0$ requires $H^2$ MGE. This makes the Schur multiplier $\mathbb{Z}_2$ a compile-time certificate for quantum advantage. The paper also introduces the Penrose empire problem as a non-quantum illustration of why $H^0$ local consistency checking cannot detect $H^1$ and $H^2$ obstructions, and discusses the $H^3$ frontier (Dijkgraaf-Witten state sums, Fibonacci anyon braiding) as the next level beyond current qubit hardware. Keywords Maslov-Gibbs Einsum, tropical semiring, Maslov dequantisation, Maslov index, Clifford group, stabiliser calculus, metaplectic group, cohomological filtration, $H^k$ tower, TWIST opcode, Origami ISA, Gottesman-Knill theorem, quantum advantage, BQP, magic states, tensor contraction, Penrose tiling, Dijkgraaf-Witten, topological quantum computation

•Jul 3, 2026•0 citations

The Generalized Semi-Clifford Conjecture Holds at Level 4

Maxwell Marcus, Sathyawageeswar Subramanian, Marcel Dall'Agnol

The Clifford hierarchy $\mathsf{C}_1 \subset \mathsf{C}_2 \subset \cdots$ was introduced by Gottesman and Chuang (arXiv:quant-ph/9908010) to characterize gates that admit fault-tolerant implementation by gate teleportation. Yet, despite its rich mathematical structure and the attention it has received in recent years, little is known about $\mathsf{C}_k$ for $k > 3$. Most progress has focused on identifying structural properties of restrictions of the hierarchy, such as diagonal gates and gates on systems of small dimension $d$ or with few qudits. The generalized semi-Clifford conjecture, proposed by Zeng et al. (arXiv:0712.2084), states that every gate in $\cup_k \mathsf{C}_k$ is, up to multiplication by Cliffords, the product of a permutation and a diagonal matrix. Beigi and Shor proved the case $d=2$, $k=3$ (arXiv:0810.5108) and Pllaha et al. found an alternative proof by exploiting fixed points of the conjugation map induced by (a Clifford correction of) $U \in \mathsf{C}_3$ on the span of maximal stabilizer subgroups (arXiv:2006.14040). By extending their fixed-point arguments to the group $Γ_1(U)$ generated by $U \mathsf{P} U^\dagger$ and beyond, we prove the conjecture for $k \leq 4$ and any prime dimension $d$. Our proof centers on conjugation groups $Γ_1(U), Γ_2(U), \ldots$ of $U \in \mathsf{C}_k$, which we expect to be a useful tool in the study of the Clifford hierarchy more generally. We also show a natural sufficient condition on such groups for gates in higher levels to be generalized semi-Clifford.

quant-pharXiv:2609.38751•Oct 1, 2026•0 citations
Establishes the H^k complexity ladder as a projective hierarchy: H0 (classical/tropical) and H1 (Clifford/stabiliser) are projective shadows of H2 (magic/metaplectic). The Meld — the H2 completion of the ISA — projects onto Origami (H0+H1 shadow) and Forge (H1 shadow) in the same way that a 3D object projects onto 2D shadows. Derives the Palmer Invariant Space-time conjecture as the fixed-point condition of Penrose objective reduction within this framework.
PENDING QUALITY AUDIT (2026-08). The file is restricted while this record is reviewed as part of a systematic audit of the author's corpus. It has not yet been assessed. Metadata and DOI remain public, and access can be requested. We complete the TRS trilogy — Origami (β→∞\beta\to\inftyβ→∞, tropical, classical), Forge (0<β<∞0<\beta<\infty0<β<∞, real, statistical), Meld (β=it\beta=itβ=it, complex, quantum) — by showing that the Meld ISA is the quantum circuit model expressed in the TRS semiring language. Three results follow. Result 1 (ISA completeness). The Clifford group equals the Meld ISA without the BIND opcode. Universal quantum computation equals Meld plus BIND. The T-gate T=diag(1,,eiπ/4)T = \mathrm{diag}(1,, e^{i\pi/4})T=diag(1,,eiπ/4) is the BIND opcode at j=12j=\tfrac{1}{2}j=21​ — the Fano associator obstruction of Paper 407, applied to qubit representations. The magic-typing classification of Papers 365/366 maps exactly onto the 731-ISA opcode hierarchy: Clifford gates occupy Fano-line orbits (SPLIT/FLIP/TWIST at Clifford angles); the T-gate occupies the non-collinear Fano triple (BIND). Result 2 (Quantum algorithm factory). Every classical algorithm of the form arg⁡max⁡g∈Gf(g)\arg\max_{g\in G} f(g)argmaxg∈G​f(g) over an abelian group GGG has a C\mathbb{C}C-MGE quantum counterpart C-MGE(f)=SPLITG⋅FLIP(f)⋅SPLAT\mathbb{C}\text{-MGE}(f) = \mathrm{SPLIT}_G \cdot \mathrm{FLIP}(f) \cdot \mathrm{SPLAT}C-MGE(f)=SPLITG​⋅FLIP(f)⋅SPLAT, giving exponential speedup via quantum Fourier sampling whenever GGG is abelian and fff has a hidden subgroup concentrating Fourier mass. Shor's algorithm decomposes into three ISA layers: Layer 1 (Origami — classical modular exponentiation), Layer 2 (Meld — QFT as SPLIT-TWIST-FLIP cascade), Layer 3 (Origami — measurement as tropical projection). "Frozen-Shor" (Origami ISA, β→∞\beta\to\inftyβ→∞) recovers classical exhaustive search at cost O(N)O(N)O(N). "Warm-Shor" (Forge ISA, real β\betaβ) gives Grover-like O(N)O(\sqrt{N})O(N​) thermal concentration. Full Shor (Meld, β=it\beta=itβ=it) achieves O(log⁡N)O(\log N)O(logN) via destructive interference — a resource unavailable in either real ISA. New algorithm candidates follow by identifying the symmetry group of the target problem: equivariant ML, quantum persistent homology (Lloyd-Garnerone-Zanardi 2016), and Boson Sampling (Aaronson-Arkhipov 2011) all fit the five-step factory template. Result 3 (ML-KEM structural no-go). ML-KEM (Module-LWE) is immune because LWE noise exponentially suppresses every Fourier component: Ee∼Dσ[ei⟨ξ,e⟩]=e−∣ξ∣2σ2/2\mathbb{E}{\mathbf{e}\sim D\sigma}[e^{i\langle\xi,\mathbf{e}\rangle}] = e^{-|\xi|^2\sigma^2/2}Ee∼Dσ[ei⟨ξ,e⟩]=e−∣ξ∣2σ2/2. No Fourier peak exists; SPLAT cannot extract a period. The deeper reason is that worst-case LWE reduces to the dihedral hidden subgroup problem (Regev 2002) — a non-abelian problem for which no efficient Meld program is known. Breaking ML-KEM would require a BIND opcode capable of distinguishing dihedral cosets, a capability not established for the current 731-Meld. The HkH^kHk complexity ladder (Paper 420) is realised by the trilogy: H0H^0H0 (tree) = Origami, H1H^1H1 (loop) = Forge/BPP, H2H^2H2 (surface) = Meld/BQP. The T-gate is the H2H^2H2 generator that lifts computation off the stabiliser submanifold into the curved interior of the Fisher information metric. Series: Paper 258 (Origami ISA) → Paper 419 (Forge ISA) → Paper 443 (⊕β\oplus_\beta⊕β​ semiring, six pairs) → Paper 453 (multi-sector Forge) → Paper 454 (this paper — Meld ISA, trilogy complete). Related identifiers (Cites) Paper 258 Origami ISA: doi:10.5281/zenodo.19916429 Paper 419 Forge ISA: doi:10.5281/zenodo.20694527 Paper 443 ⊕_β semiring: doi:10.5281/zenodo.20752384 Paper 407 Associamancy: doi:10.5281/zenodo.20702223 Paper 365 Fano Magic Factory: doi:10.5281/zenodo.20541583 Paper 366 CS Magic Composition: doi:10.5281/zenodo.20541665 Paper 445 Kitaev anyons: doi:10.5281/zenodo.20752352 Paper 453 Multi-sector Forge: doi:10.5281/zenodo.20773423 Paper 420 H^k complexity ladder: doi:10.5281/zenodo.20773526
A fundamental problem in fault-tolerant quantum computation is the tradeoff between universality and dimensionality, exemplified by the the Bravyi-König bound for nnn-dimensional topological stabilizer codes. In this work, we extend topological Pauli stabilizer codes to a broad class of nnn-dimensional Clifford hierarchy stabilizer codes. These codes correspond to the (n+1)(n+1)(n+1)D Dijkgraaf-Witten gauge theories with non-Abelian topological order. We construct transversal non-Clifford gates through automorphism symmetries represented by cup products. In 2D, we obtain the first transversal non-Clifford logical gates including T and CS for Clifford stabilizer codes, using the automorphism of the twisted Z23\mathbb{Z}_2^3Z23​ gauge theory (equivalent to D4\mathbb{D}_4D4​ topological order). We also combine it with the just-in-time decoder to fault-tolerantly prepare the logical T magic state in O(d)O(d)O(d) rounds via code switching. In 3D, we construct a transversal logical T\sqrt{\text{T}}T​ gate in a non-Clifford stabilizer code at the third level of the Clifford hierarchy, located on a tetrahedron corresponding to a twisted Z24\mathbb{Z}_2^4Z24​ gauge theory. Our constructions surpass the Bravyi-König bound by achieving the logical gates in the (n+1)(n+1)(n+1)-th level of Clifford hierarchy in nnn spatial dimension.
The Maslov-Gibbs Einsum (MGE) is not a single algorithm but a family of tensor contraction schemes indexed by the cohomological level HkH^kHk of the physical system. This paper identifies three distinct forms: H0H^0H0 MGE (classical/tropical): contraction over the min-plus tropical semiring, corresponding to Maslov dequantisation (ℏ→0\hbar \to 0ℏ→0). Finds the dominant classical path; computational class P. H1H^1H1 MGE (Clifford/stabiliser): contraction over the stabiliser calculus of the Clifford group C2\mathsf{C}_2C2​. Captures quantum interference within the stabiliser sector. Classically simulable in polynomial time by the Gottesman-Knill theorem, but exponentially more expressive than H0H^0H0: captures non-local correlations, entanglement, and quantum error correction. H2H^2H2 MGE (metaplectic/magic): contraction with Maslov index phase corrections. Each gate composition g∘hg \circ hg∘h acquires a Z2\mathbb{Z}_2Z2​ phase factor (−1)τ(L,gL,ghL)(-1)^{\tau(L, gL, ghL)}(−1)τ(L,gL,ghL) from the Maslov index of three Lagrangian subspaces. The TWIST opcode in the Origami ISA counts how many times this correction fires; TWIST >0> 0>0 is necessary and sufficient for H2H^2H2 MGE. Computational class BQP-hard. The central observation is that Viktor Maslov named both ends of this ladder: Maslov dequantisation (H0H^0H0, 1990s) and the Maslov index (H2H^2H2, 1965) are not coincidentally related — they are the two limits of the same quantisation programme, with the Clifford/Berry-phase level H1H^1H1 interpolating between them. The name "Maslov-Gibbs Einsum" was more prophetic than intended: Maslov's index governs the H2H^2H2 correction as well as the H0H^0H0 tropical limit. The Origami ISA compiler selects the MGE form automatically: TWIST =0= 0=0 implies H1H^1H1 MGE suffices; TWIST >0> 0>0 requires H2H^2H2 MGE. This makes the Schur multiplier Z2\mathbb{Z}_2Z2​ a compile-time certificate for quantum advantage. The paper also introduces the Penrose empire problem as a non-quantum illustration of why H0H^0H0 local consistency checking cannot detect H1H^1H1 and H2H^2H2 obstructions, and discusses the H3H^3H3 frontier (Dijkgraaf-Witten state sums, Fibonacci anyon braiding) as the next level beyond current qubit hardware. Keywords Maslov-Gibbs Einsum, tropical semiring, Maslov dequantisation, Maslov index, Clifford group, stabiliser calculus, metaplectic group, cohomological filtration, HkH^kHk tower, TWIST opcode, Origami ISA, Gottesman-Knill theorem, quantum advantage, BQP, magic states, tensor contraction, Penrose tiling, Dijkgraaf-Witten, topological quantum computation
The Clifford hierarchy C1⊂C2⊂⋯\mathsf{C}_1 \subset \mathsf{C}_2 \subset \cdotsC1​⊂C2​⊂⋯ was introduced by Gottesman and Chuang (arXiv:quant-ph/9908010) to characterize gates that admit fault-tolerant implementation by gate teleportation. Yet, despite its rich mathematical structure and the attention it has received in recent years, little is known about Ck\mathsf{C}_kCk​ for k>3k > 3k>3. Most progress has focused on identifying structural properties of restrictions of the hierarchy, such as diagonal gates and gates on systems of small dimension ddd or with few qudits. The generalized semi-Clifford conjecture, proposed by Zeng et al. (arXiv:0712.2084), states that every gate in ∪kCk\cup_k \mathsf{C}_k∪k​Ck​ is, up to multiplication by Cliffords, the product of a permutation and a diagonal matrix. Beigi and Shor proved the case d=2d=2d=2, k=3k=3k=3 (arXiv:0810.5108) and Pllaha et al. found an alternative proof by exploiting fixed points of the conjugation map induced by (a Clifford correction of) U∈C3U \in \mathsf{C}_3U∈C3​ on the span of maximal stabilizer subgroups (arXiv:2006.14040). By extending their fixed-point arguments to the group Γ1(U)Γ_1(U)Γ1​(U) generated by UPU†U \mathsf{P} U^\daggerUPU† and beyond, we prove the conjecture for k≤4k \leq 4k≤4 and any prime dimension ddd. Our proof centers on conjugation groups Γ1(U),Γ2(U),…Γ_1(U), Γ_2(U), \ldotsΓ1​(U),Γ2​(U),… of U∈CkU \in \mathsf{C}_kU∈Ck​, which we expect to be a useful tool in the study of the Clifford hierarchy more generally. We also show a natural sufficient condition on such groups for gates in higher levels to be generalized semi-Clifford.