PairCurvatureInequality
Abstract
Positivity and strict ratio growth for the two-coordinate curvature pair.
Definition 1.1 (E).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
Evaluation of the elementary symmetric polynomial gives the elementary symmetric sum of the real coordinates.
Definition 1.2 (P).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.P (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
Evaluation of the power-sum polynomial gives the sum of the kth powers of the real coordinates.
Lemma 1.3 (E_evalSum).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E_evalSum (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The evaluated elementary symmetric polynomial is the sum of coordinate products over k-element subsets.
Lemma 1.4 (P_evalSum).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.P_evalSum (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The evaluated power-sum polynomial is the finite sum of kth powers.
Lemma 1.5 (E_one_eq_sum).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E_one_eq_sum (✓ std3). ∎
Citation. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The first elementary symmetric sum is the coordinate sum.
Lemma 1.6 (newton2).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton2 (✓ std3). ∎
Citation. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The second Newton identity relates the square sum to the first two elementary symmetric sums.
Lemma 1.7 (newton3).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton3 (✓ std3). ∎
Citation. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The third Newton identity expresses the cube sum through the coordinate sum and the second and third elementary symmetric sums.
Lemma 1.8 (newton4).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton4 (✓ std3). ∎
Citation. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The fourth Newton identity expresses the fourth-power sum through the first four elementary symmetric sums.
Definition 1.9 (pairT).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairT (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The quadratic power sum after separating two coordinates is u squared minus twice their product v, plus the rest square sum B.
Definition 1.10 (pairN).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairN (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The elementary-symmetric curvature numerator is expressed through the pair sum u, pair product v and remaining elementary symmetric sums.
Definition 1.11 (pairK).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairK (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
This polynomial controls the sign of curvature growth as the pair product increases at fixed pair sum.
Definition 1.12 (pairR).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairR (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The pair curvature is twice pairN divided by the square of pairT.
Definition 1.13 (mixProduct).
Formalization. D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.mixProduct (✓ std3).
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
This is the product of the two coordinates after convex mixing with their swap.
Theorem 1.14 (coordinateB_le_sum_sq).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinateB_le_sum_sq (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
For nonnegative coordinates, the square sum is bounded above by the square of the coordinate sum.
Theorem 1.15 (coordinateB_pos).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinateB_pos (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
A positive coordinate makes the square sum strictly positive.
Theorem 1.16 (key_pos).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.key_pos (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
Separating u at one half and bounding the coefficient of v proves the displayed strict estimate.
Theorem 1.17 (pairT_pos).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairT_pos (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The product bound v≤u²/4 and positivity of B keep the quadratic denominator positive.
Theorem 1.18 (ratio_strict_increase).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.ratio_strict_increase (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
Positivity of pairK at both endpoints and of both denominators gives strict growth of the rational curvature ratio.
Theorem 1.19 (coordinate_key_pos).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinate_key_pos (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
The Newton identities and the nonnegative square decomposition put the remaining coordinates into the strict pair estimate.
Theorem 1.20 (ttransform_product_increase).
Proof. Machine-checked in Lean as D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.ttransform_product_increase (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Paolo Gibilisco; Tommaso Isola (2005). On the monotonicity of scalar curvature in classical and quantum information geometry. DOI: 10.1063/1.1834693. URL: https://arxiv.org/abs/math-ph/0407007v2.
Acknowledgement. Mathlib contributors (2026). Mathlib symmetric polynomial definitions and Newton identities. URL: https://github.com/leanprover-community/mathlib4/blob/db584cd6d46c92f209a44c0f1c829460d327499d/Mathlib/RingTheory/MvPolynomial/Symmetric/NewtonIdentities.lean.
Commentary.
Interior mixing of two unequal coordinates strictly increases their product.
References
- Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E_evalSum - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.E_one_eq_sum - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.P - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.P_evalSum - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinateB_le_sum_sq - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinateB_pos - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.coordinate_key_pos - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.key_pos - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.mixProduct - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton2 - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton3 - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.newton4 - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairK - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairN - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairR - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairT - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.pairT_pos - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.ratio_strict_increase - Truth anchor:
D5/S3/Geometry/AlphaGeometry/PairCurvatureInequality.ttransform_product_increase