MATHLIBANNEX / PROJECT LFH

Finite-stage purification and local transport

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Scope

Finite Gram matrices and matrix units purify vector states on a chosen finite stage. Corner amplification turns this transport into almost-central unitary paths, with different stage choices for protected-set and unrestricted approximation.

6 direct Cards + 8 reused prerequisites = 14 unique Cards. This count is a selected Card closure, not a source-declaration count.

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Cards in this route

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Reference index: direct Cards and reused prerequisites

Direct references: 13 — Realizing a finite Gram matrix in a represented CAR corner · 15 — Lifting a corner involution to an ambient CAR unitary · 14 — Purifying a vector state on a finite CAR stage · 16 — Exact vector transport along an almost central unitary path · 17 — Cross-representation state approximation with a protected finite set · 18 — Approximating another vector state along a unitary path

Reused prerequisites: 3 — The product-vector state on the completed CAR algebra · 10 — Root compression becomes scalar in norm · 6 — A finite-row average centralizes its matrix stage · 9 — The decreasing root projections in the CAR completion · 2 — The CAR algebra as a completion of finite matrix stages · 12 — An irreducible CAR representation has no nonzero compact image · 11 — Simplicity of the completed CAR algebra · 5 — The completed CAR algebra is infinite-dimensional

Detailed route conditions

A represented root corner has enough Hilbert-space dimension to realize any finite Gram matrix. Matrix-unit reconstruction then purifies a vector state on a selected finite stage. Supported self-adjoint interpolation and corner amplification turn finite vector transport into unitary paths; the approximate state tests concern every matrix entry, not only diagonal entries.

The protected-set theorem chooses its stage and tolerance before the later state-approximation request. The unrestricted theorem instead purifies on a large stage and transports at stage zero, where the sole unit-vector test is automatic. These are different stages. The fixed-stage abbreviation , the finite-dimensional interpolation space , and the amplification are local objects, not the later shell links or trace-GNS unitary .

Reference index: exact Card references

Exact Card references

Dependency-first reading route

Read selected Card prerequisites before their uses. Levels are recomputed from the selected reachability-preserving projection; omitted source helpers remain traceable in the source exploration.

14 Cards

Level 0 (1 Card)

Level 0

The CAR algebra as a completion of finite matrix stages

Names the completed CAR algebra in which finite matrix calculations can be extended by norm approximation.

MathlibAnnex.CStarAlgebra.CAR.Limit

Level 1 (4 Cards)

Level 1

A finite-row average centralizes its matrix stage

Turns an arbitrary element of the completed CAR algebra into one commuting with a prescribed finite matrix stage.

MathlibAnnex.CStarAlgebra.CAR.ofStage_commute_rowAverage

Level 2 (1 Card)

Level 3 (1 Card)

Level 4 (1 Card)

Level 4

An irreducible CAR representation has no nonzero compact image

Simplicity and infinite dimensionality rule out compact operators coming from nonzero CAR elements.

MathlibAnnex.CStarAlgebra.CAR.eq_zero_of_isCompactOperator_image

Level 5 (2 Cards)

Level 5

Lifting a corner involution to an ambient CAR unitary

A prescribed unitary involution on a represented root corner can be realized on finitely many vectors by one lifted corner exponential.

MathlibAnnex.CStarAlgebra.CAR.exists_liftedCornerExponential_apply_eq_involution

Level 6 (2 Cards)

Level 6

Purifying a vector state on a finite CAR stage

Every finite-stage restriction of a unit vector state can be realized by a unit vector in any irreducible CAR representation.

MathlibAnnex.CStarAlgebra.CAR.exists_unitVector_vectorFunctional_eq_on_stage

Level 6

Exact vector transport along an almost central unitary path

Finite matrix-state tests ensure exact transport while protecting a prescribed finite set throughout the path.

MathlibAnnex.CStarAlgebra.CAR.exists_stageTests_exact_unitary_path_apply_eq_and_conjugate_sub_norm_lt

Level 7 (2 Cards)

Level 7

Approximating another vector state along a unitary path

A fixed irreducible CAR representation can approximate any vector state on finitely many elements by moving a given unit vector.

MathlibAnnex.CStarAlgebra.CAR.exists_unitary_crossRepresentation_path_approx

Level 7

Cross-representation state approximation with a protected finite set

Finite entrywise tests allow new state approximation while an entire unitary path nearly fixes earlier data.

MathlibAnnex.CStarAlgebra.CAR.exists_stageTests_crossRepresentation_path_approx

Immediate Card prerequisites: Purifying a vector state on a finite CAR stage · Exact vector transport along an almost central unitary path

Used by in this scope: None in this selected scope

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