lattice-system

Legacy catalogue: Generic matrix-analysis helpers (Math/MatrixAnalysis/)

Interim authority. This lossless catalogue chunk remains authoritative for formalization status and capstone identification until Issue #5228. The version 1 JSON catalogue is still a non-authoritative prototype.

Interim catalogueSpin foundations and Tasaki Chapter 2

Generic matrix-analysis helpers (Math/MatrixAnalysis/)

Topic-organized generic linear-algebra facts extracted from the physics files where they had been re-proved as private helpers (Issue #4339).

Lean name Statement File
Matrix.isHermitian_sum a finite sum of Hermitian matrices is Hermitian Math/MatrixAnalysis/HermitianSum.lean
Matrix.IsHermitian.mul_of_commute the product of two commuting Hermitian matrices is Hermitian Math/MatrixAnalysis/HermitianSum.lean
Matrix.noncommProd_isHermitian a Finset.noncommProd of pairwise-commuting Hermitian matrices is Hermitian Math/MatrixAnalysis/NoncommProd.lean
Matrix.noncommProd_sq_of_sq_one a Finset.noncommProd of pairwise-commuting involutions is an involution Math/MatrixAnalysis/NoncommProd.lean
Matrix.noncommProd_mul_self_of_idempotent a Finset.noncommProd of pairwise-commuting idempotents is idempotent Math/MatrixAnalysis/NoncommProd.lean
Matrix.noncommProd_mulVec_eq_self a Finset.noncommProd of matrices each fixing ψ also fixes ψ Math/MatrixAnalysis/NoncommProd.lean
Matrix.IsHermitian.trace_im the trace of a Hermitian matrix is real Math/MatrixAnalysis/HermitianTrace.lean
Matrix.trace_mul_star_of_isHermitian Tr(A·B) of two Hermitian matrices is conjugation-invariant Math/MatrixAnalysis/HermitianTrace.lean
rayleighOnVec_mono Loewner monotonicity of the unnormalised energy quadratic form: A ≤ B implies rayleighOnVec A v ≤ rayleighOnVec B v for every v — the pointwise input to the eigenvalue comparison of Tasaki Theorem A.7 (§A.2, p. 468) (PR #5149) Math/MatrixAnalysis/CourantFischer.lean

(The two trace helpers above are also listed in the Gibbs-state section where they are consumed; the canonical definitions live in Math/MatrixAnalysis/HermitianTrace.lean.)

These are consumed by the Jordan–Wigner string / Hubbard hard-core projection layers (PR #4342), replacing the per-file private copies in Fermion/JWAbstract.lean, Fermion/JordanWigner/Operators.lean, and Fermion/JordanWigner/Hubbard/HardcoreProjection.lean.


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