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A product decomposition of the generalized CHSH groups

Abstract

For every n at least two, the presented generalized CHSH group is a semidirect product of C_(2n) x C_2^(n-2) by C_n, with an explicit cyclic action.

Definition 1.1 (The first free generator).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.P0 (✓ std3).

Citation. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

P0 is generator 0 of FreeGroup (Fin 3), representing the paper’s P_0.

Definition 1.2 (The second free generator).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.P1 (✓ std3).

Citation. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

P1 is generator 1 of FreeGroup (Fin 3), representing the paper’s P_1.

Definition 1.3 (The central free generator).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.J (✓ std3).

Citation. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

J is generator 2 of FreeGroup (Fin 3), representing the paper’s J.

Definition 1.4 (The relator set).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.rels (✓ std3).

Citation. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

Section 5, printed p. 24, defines: G_n = <P_0, P_1, J | P_0^n, P_1^n, J^n, [J, P_0], [J, P_1], J^i(P_0^iP_1^(-i))^2 for 1 <= i <= floor(n/2)>. These words are equal to the identity. The index i is natural; its negated exponent is cast to the integers. Nat.div n 2 is natural division, with value floor(n/2).

Definition 1.5 (The presented group).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.G (✓ std3).

Citation. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

G n is the quotient of the free group on these three generators by the normal closure of rels n, the group G_n of Section 5.

Definition 1.6 (The abelian factor).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.L (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

L n is C_(2n) times n-2 independent copies of C_2. Fin (n-2) indexes the independent involutions; subtraction here is natural subtraction.

Definition 1.7 (A homomorphism out of a cyclic group).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.cyclicHom (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

For a^n = 1, cyclicHom sends the additive residue of an integer j to a^j. It uses the additive universal map ZMod.lift and the multiplicative type conversion. The parenthesized proposition in the subtype constructor is its constructor proof field: zmultiplesHom sends the integer n to zero.

Theorem 1.8 (Evaluation on an integer residue).

Proof. Machine-checked in Lean as D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.cyclicHom_int (✓ std3). ∎

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

For every group H, natural n, element a with a^n = 1 and integer i, cyclicHom n a ha sends ofAdd (i : ZMod n) to the integer power a^i.

Definition 1.9 (The cyclic generator).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.s (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

The first component is 1 in ZMod (2*n), converted to multiplicative notation; the function component is constantly the identity.

Definition 1.10 (The independent involutions).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.t (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

t n i has first component 1 and is 1 except for ofAdd 1 at i in its function component. The paper’s one-based index is i.val+1.

Definition 1.11 (The homomorphism from the abelian factor).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.liftL (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

The images a and b i satisfy a^(2*n) = 1, (b i)^2 = 1 and commute pairwise. noncommPiCoprod forms the map from the involution factors and noncommCoprod joins it to the cyclic factor. The parenthesized propositions display the full proof arguments: images from distinct involution factors commute, and each cyclic-factor image commutes with each image of the involution product.

Definition 1.12 (The product of independent involutions).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.ts (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

ts multiplies all independent involutions over Fin (n-2); the product is 1 when n = 2.

Definition 1.13 (The dependent last involution).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.u (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

For 1 <= k <= n-2, u n k is t n at the finite index k-1. At k = n-1 outside that interval it is s n raised to n times ts n; at all other indices it is 1. The parenthesized proposition k-1 < n-2 is the Fin constructor proof field under the first branch’s condition. This definition also fixes the values for n below two.

Definition 1.14 (The cyclic orbit coordinates).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.e (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

e n k is s n times the k-th extended involution. For n at least two, e n 0 = e n n = s n.

Definition 1.15 (One cyclic step).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.step (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

step sends s to e n 1 and each t n i to e n (i.val+2) times the inverse of e n 1. Its four parenthesized proof arguments assert order dividing 2*n for the first image, square one for each involution image, pairwise commutation of those images, and their commutation with the first image.

Definition 1.16 (The cyclic automorphism).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.stepAut (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

For n at least two, step iterated n times is the identity on L n. stepAut has forward function step n and inverse function the (n-1)-fold iterate of step n. The parenthesized propositions are constructor proof fields: the two Equiv.mk fields assert the inverse identities for every x in L n, and the MulEquiv.mk field asserts preservation of multiplication for every x and y in L n.

Definition 1.17 (The action of C_n).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.alpha (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

For n at least two, alpha maps ofAdd 1 to stepAut n. Thus alpha(s) = s times u n 1 and alpha(t n i) = u n (i.val+2) times u n 1. The dependent last involution gives the wrap-around. The parenthesized proof argument asserts that stepAut n hn raised to n is the identity automorphism under the branch hypothesis hn. For n below two, alpha is the constant identity homomorphism.

Definition 1.18 (The uniform decomposition).

Formalization. D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.claim (✓ std3).

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

Section 1.4 (Further work), item 2, printed p. 7: “In Section 5, we give efficient explicit presentations for G_n and its multiplication table. Can we go further and characterize these groups in terms of direct and semidirect products of small well-known groups? The first few cases are as follows” The encoding answers this question for every natural n >= 2 by an actual multiplicative equivalence. C_m is Multiplicative (ZMod m); the elementary abelian factor uses Fin (n-2), and alpha is the displayed action.

Theorem 1.19 (The decomposition theorem).

Proof. Machine-checked in Lean as D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.result (✓ std3). ∎

Resolves. Problems/cui-mehta-mousavi-nezhadi-2020-chsh-group-decomposition (proved) by D5/S3/Quantum/Algebra/GeneralizedCHSHGroupDecomposition.result.

Source. Repository-derived.

Acknowledgement. D. Cui; A. Mehta; H. Mousavi; S. S. Nezhadi (2020). A generalization of CHSH and the algebraic structure of optimal strategies. DOI: 10.22331/q-2020-10-21-346. URL: https://arxiv.org/abs/1911.01593.

Commentary.

The forward homomorphism sends P0 to inr(ofAdd 1), P1 to inl(s) times inr(ofAdd 1), and J to inl(s^2). In the presented group, the elements P0^i P1^(-i) commute, allowing the inverse map from L. Its compatibility with conjugation by P0 gives a homomorphism from the semidirect product. Both composites fix the generators, so the maps form a multiplicative equivalence. No group-order computation is used.

References