MATHLIBANNEX / PROJECT LFH

One C*-algebra and its representation-theoretic properties

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Scope

The chosen homogeneity family defines one fixed unital simple infinite-dimensional algebra with a unique nonzero irreducible representation class. It also has a faithful representation on a separable trace space but no nonzero separable irreducible representation.

7 direct Cards + 54 reused prerequisites = 61 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: 60 — The C*-algebra generated by the CAR representation and the shell unitaries · 62 — A simple C*-algebra with a unique irreducible representation class · 61 — The ambient representation of the fixed algebra · 63 — The fixed algebra on the CAR trace Hilbert space · 64 — Faithfulness of the representation on the CAR trace Hilbert space · 65 — No nonzero irreducible representation on a separable Hilbert space · 66 — A separably represented C*-algebra with no separable irreducible representation

Reused prerequisites: 38 — The atomic common range is one embedded GNS line · 14 — Purifying a vector state on a finite CAR stage · 43 — The ambient inclusion of the fixed shell-family target · 3 — The product-vector state on the completed CAR algebra · 26 — Choosing the CAR shell family from proved homogeneity · 19 — Approximately inner homogeneity of pure CAR states · 57 — The target represented on the CAR trace GNS space · 55 — The GNS representation of the target trace extension · 10 — Root compression becomes scalar in norm · 27 — The selected GNS representation of a pure-state class · 36 — The matching GNS fiber retains exactly its cyclic line · 28 — Distinct GNS classes have no unitary intertwiner · 49 — The shell-generated algebra is not an algebra of all compact operators · 50 — Structural properties of one shell-generated C*-algebra · 56 — Faithfulness of the target-state GNS representation · 29 — The atomic direct sum of the selected CAR representations · 15 — Lifting a corner involution to an ambient CAR unitary · 16 — Exact vector transport along an almost central unitary path · 46 — Every irreducible representation is unitarily equivalent to the inclusion · 33 — Realizing a shell family by a faithful irreducible operator algebra · 42 — The CAR source map into the fixed shell-family target · 34 — Shell matching fixes the trace of transported flags · 1 — The normalized trace on a finite CAR stage · 35 — Transported flags vanish on vectors generated by a trace vector · 18 — Approximating another vector state along a unitary path · 6 — A finite-row average centralizes its matrix stage · 17 — Cross-representation state approximation with a protected finite set · 9 — The decreasing root projections in the CAR completion · 48 — Closed-ideal simplicity of the shell-generated algebra · 4 — Purity of the completed root state · 30 — An irreducible operator algebra constructed from projection shells · 51 — Extending the CAR trace to the fixed shell target · 7 — Constructing the normalized trace on the completed CAR algebra · 2 — The CAR algebra as a completion of finite matrix stages · 37 — An inequivalent GNS fiber has no residual common range · 21 — Two-sided inner sequences imply pure-state homogeneity · 40 — An irreducible target representation has a surviving fixed space · 39 — Reconstructing a represented unitary from its shells and residual corner · 24 — Exact projection links for one approximately inner automorphism · 25 — A fixed representative family of CAR shell data · 58 — Faithfulness of the representation on the CAR trace Hilbert space · 47 — Unitary equivalence without an initial unitality assumption · 22 — Pure CAR states admit two-sided inner intertwining sequences · 13 — Realizing a finite Gram matrix in a represented CAR corner · 31 — The atomic-shell construction on selected pure-GNS fibers · 32 — The closed operator algebra generated by a representation and extra operators · 12 — An irreducible CAR representation has no nonzero compact image · 45 — The cyclic sum fills every irreducible target representation · 11 — Simplicity of the completed CAR algebra · 23 — Pure-state homogeneity of the completed CAR algebra · 5 — The completed CAR algebra is infinite-dimensional · 20 — A two-sided inner intertwining sequence for two states · 41 — A common root vector realizes every selected state through the generators · 44 — Assembling selected GNS cyclic subspaces into an isometric source representation

Detailed route conditions

Specialize the supplied family to the once-chosen homogeneity family. The algebra remains , with inclusion . The structural theorem gives its faithful irreducible inclusion and the unique nonzero irreducible representation class, including possibly nonunital inputs.

The same acts faithfully on the separable CAR trace space by . It has no nonzero irreducible representation on a separable Hilbert space. The proof first establishes unit preservation and composes the two classification unitaries in the direction before applying the finite-dimensionality theorem. This does not rule out its irreducible inclusion on the nonseparable atomic space.

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.

61 Cards

Level 0 (6 Cards)

Level 0

The selected GNS representation of a pure-state class

A choice of representative pure states, fixed literally at a root, gives one concrete GNS representation per equivalence class.

MathlibAnnex.CStarAlgebra.PureState.selectedRepresentation

Level 0

Exact projection links for one approximately inner automorphism

A point-norm approximation followed by close-projection conjugacy gives exact support identities for an arbitrary projection family.

MathlibAnnex.CStarAlgebra.exists_shell_family_of_approximately_inner

Immediate Card prerequisites: None in this selected scope

Used by in this scope: Choosing the CAR shell family from proved homogeneity

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 0

A fixed representative family of CAR shell data

One family records a transporting automorphism and exact shell links for each selected pure-state class, with an explicitly fixed root component.

MathlibAnnex.CStarAlgebra.CAR.RepresentativeShellFamily

Level 0

The closed operator algebra generated by a representation and extra operators

Places a represented algebra and a chosen family of bounded operators in one concrete closed algebra.

MathlibAnnex.CStarAlgebra.AtomicConstruction.concreteTarget

Level 1 (9 Cards)

Level 1

A two-sided inner intertwining sequence for two states

An inner sequence records both forward and actual inverse convergence data before any limiting automorphism is constructed.

MathlibAnnex.CStarAlgebra.CAR.HasInnerIntertwiningSequence

Level 1

Constructing the normalized trace on the completed CAR algebra

Carries compatible bounded matrix traces through the algebraic limit, normed union and completion.

MathlibAnnex.CStarAlgebra.CAR.trace

Level 1

An irreducible operator algebra constructed from projection shells

Shell partial isometries with rank-one limiting defects can be completed to unitary links that join inequivalent irreducible fibers.

MathlibAnnex.CStarAlgebra.AtomicConstruction.exists_irreducible_atomicShellModel

Level 1

Distinct GNS classes have no unitary intertwiner

The class index makes the selected pure-GNS family pairwise unitarily inequivalent.

MathlibAnnex.CStarAlgebra.PureState.no_unitaryIntertwiner_selectedRepresentation

Level 1

The decreasing root projections in the CAR completion

The distinguished stage corners give a nested sequence of projections supporting the root state.

MathlibAnnex.CStarAlgebra.CAR.rootFlag

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 (5 Cards)

Level 2

Root compression becomes scalar in norm

Extends an exact rank-one compression identity on finite stages to a pointwise norm limit on the completed algebra.

MathlibAnnex.CStarAlgebra.CAR.tendsto_norm_compressionError

Level 2

Purity of the completed root state

Passes extremality of the root vector states from every finite matrix stage to the completed CAR algebra.

MathlibAnnex.CStarAlgebra.CAR.isPureState_rootState

Level 2

The atomic-shell construction on selected pure-GNS fibers

Pure-state GNS data supplies the irreducible and inequivalent fibers required by the generic shell construction.

MathlibAnnex.CStarAlgebra.AtomicConstruction.exists_irreducible_pureAtomicShellModel

Level 2

Shell matching fixes the trace of transported flags

Recovers exact trace values from the initial and final supports of shell links.

MathlibAnnex.CStarAlgebra.CAR.trace_transportedFlag

Level 2

Two-sided inner sequences imply pure-state homogeneity

The forward and inverse limits close the homogeneity argument once an intertwining sequence is supplied for every pure-state pair.

MathlibAnnex.CStarAlgebra.CAR.homogeneity_of_innerIntertwiningSequences

Level 3 (5 Cards)

Level 3

The atomic direct sum of the selected CAR representations

All selected pure-GNS fibers of the completed CAR algebra act together on one Hilbert direct sum.

MathlibAnnex.CStarAlgebra.CAR.selectedAtomicRepresentation

Level 3

The matching GNS fiber retains exactly its cyclic line

Identifies the residual projection of a transported CAR flag in its matching pure-state representation.

MathlibAnnex.CStarAlgebra.CAR.selected_commonFixedProjection_eq_rankOne

Level 3

An inequivalent GNS fiber has no residual common range

Uses compression and cyclic transport to exclude fixed vectors in every other chosen pure-state class.

MathlibAnnex.CStarAlgebra.CAR.selected_commonFixedProjection_eq_zero

Level 4 (4 Cards)

Level 4

The atomic common range is one embedded GNS line

Assembles the matching and inequivalent fiber calculations in an arbitrary Hilbert direct sum.

MathlibAnnex.CStarAlgebra.CAR.iInf_range_atomic_transportedFlag_eq_span

Level 4

Assembling selected GNS cyclic subspaces into an isometric source representation

Joins mutually orthogonal pure-state cyclic copies and controls the limiting flag projections on their sum.

MathlibAnnex.CStarAlgebra.CAR.exists_selectedAtomicCyclicIsometry

Level 4

Reconstructing a represented unitary from its shells and residual corner

Separates a represented generator into a strong shell sum and the exact operator between its limiting fixed spaces.

MathlibAnnex.CStarAlgebra.CAR.exists_targetShellReconstruction

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 (4 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 5

Realizing a shell family by a faithful irreducible operator algebra

Constructs unitary links between pure-state summands and an irreducible algebra containing a faithful copy of CAR.

MathlibAnnex.CStarAlgebra.CAR.exists_completedAtomicShellModel

Level 5

An irreducible target representation has a surviving fixed space

Rules out simultaneous disappearance of all limiting CAR flags by passing reduction through the reconstructed generators.

MathlibAnnex.CStarAlgebra.CAR.exists_nonzero_targetFixedSpace

Level 6 (5 Cards)

Level 6

A common root vector realizes every selected state through the generators

Builds a compatible family of unit vectors from a surviving residual space and identifies their CAR vector states.

MathlibAnnex.CStarAlgebra.CAR.exists_targetDefectVectorFamily

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 6

The CAR source map into the fixed shell-family target

Restricting the codomain of the selected atomic representation gives the source map into one fixed generated target.

MathlibAnnex.CStarAlgebra.CAR.shellFamilySourceHom

Level 6

The ambient inclusion of the fixed shell-family target

The same concrete target has a literal representation on the selected atomic Hilbert space.

MathlibAnnex.CStarAlgebra.CAR.shellFamilyInclusion

Level 7 (5 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

The shell-generated algebra is not an algebra of all compact operators

Excludes an injective representation of the infinite-dimensional unital algebra onto all compact operators.

MathlibAnnex.CStarAlgebra.CAR.not_isCompactOperatorModel_shellFamilyTarget

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

Level 7

The cyclic sum fills every irreducible target representation

Uses shell reconstruction and residual lines to turn an isometric CAR intertwiner into a unitary equivalence on the source.

MathlibAnnex.CStarAlgebra.CAR.exists_surjective_selectedAtomicCyclicIsometry

Level 8 (3 Cards)

Level 8

Every irreducible representation is unitarily equivalent to the inclusion

Extends the unitary equivalence from the CAR source to all additional generators and the norm-closed target.

MathlibAnnex.CStarAlgebra.CAR.ambientInclusion_unitaryEquivalent

Level 8

Pure CAR states admit two-sided inner intertwining sequences

Finite-set vector-state transport supplies explicit corrections; their summable conjugation bounds and state estimates yield the required two-sided sequence.

MathlibAnnex.CStarAlgebra.CAR.hasInnerIntertwiningSequence_of_pure

Level 9 (4 Cards)

Level 9

The target represented on the CAR trace GNS space

A fixed pointed unitary transports the target action onto the Hilbert space constructed from CAR alone.

MathlibAnnex.CStarAlgebra.CAR.traceModelRepresentation

Level 9

Unitary equivalence without an initial unitality assumption

Shows why allowing nonunital input representations does not enlarge the irreducible representation class of the shell-generated algebra.

MathlibAnnex.CStarAlgebra.CAR.shellFamilyInclusion_unitaryEquivalent_nonUnital

Level 9

Pure-state homogeneity of the completed CAR algebra

The constructed inner intertwining sequences discharge the supplier hypothesis and give an approximately inner transporting automorphism.

MathlibAnnex.CStarAlgebra.CAR.homogeneity

Level 9

Closed-ideal simplicity of the shell-generated algebra

Uses a faithful irreducible representation in the unique unitary-equivalence class to rule out proper nonzero closed two-sided ideals.

MathlibAnnex.CStarAlgebra.CAR.isSimpleCStarAlgebra_shellFamilyTarget

Level 10 (3 Cards)

Level 10

Choosing the CAR shell family from proved homogeneity

CAR homogeneity and exact shell matching supply one family whose distinguished component is fixed by an explicit identity choice.

MathlibAnnex.CStarAlgebra.CAR.homogeneityShellFamily

Level 10

Structural properties of one shell-generated C*-algebra

Collects the proved properties of a single generated algebra, keeping the shell-family input separate from its consequences.

MathlibAnnex.CStarAlgebra.CAR.shellFamilyEndpoint

Level 10

Faithfulness of the target-state GNS representation

The ideal dichotomy of the same target forces the constructed nonzero representation to be injective.

MathlibAnnex.CStarAlgebra.CAR.tracialRepresentation_injective

Level 11 (3 Cards)

Level 11

The C*-algebra generated by the CAR representation and the shell unitaries

Defines the single algebra used in the irreducible and separable faithful representations.

MathlibAnnex.CStarAlgebra.CAR.AtomicCounterexampleAlgebra

Level 11

A simple C*-algebra with a unique irreducible representation class

Establishes the properties that make the fixed algebra a counterexample to Naimark’s problem.

MathlibAnnex.CStarAlgebra.CAR.atomicCounterexampleEndpoint

Level 12 (2 Cards)

Level 12

The fixed algebra on the CAR trace Hilbert space

Defines a representation of the same algebra on the GNS Hilbert space of the CAR trace.

MathlibAnnex.CStarAlgebra.CAR.separableCounterexampleRepresentation

Level 13 (2 Cards)

Level 13

Faithfulness of the representation on the CAR trace Hilbert space

Proves that the representation is injective.

MathlibAnnex.CStarAlgebra.CAR.separableCounterexampleRepresentation_injective

Level 13

No nonzero irreducible representation on a separable Hilbert space

Rules out irreducible representations of on separable Hilbert spaces by the finite-dimensionality theorem for a single irreducible representation class.

MathlibAnnex.CStarAlgebra.CAR.not_isIrreducible_of_separable

Level 14 (1 Card)

Level 14

A separably represented C*-algebra with no separable irreducible representation

The same algebra has a faithful representation on a separable Hilbert space, but no nonzero irreducible representation on any separable Hilbert space.

MathlibAnnex.CStarAlgebra.CAR.atomicCounterexampleEndpoint_and_exists_separable_faithful_representation_and_no_separable_irreducible_representation

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