MATHLIBANNEX / CANONICAL DECLARATION CARD

Representations without a unit-preservation requirement

MathlibAnnex.Analysis.CStarAlgebra.NonUnitalCStarRepresentation

abbrev

Names -representations of a complex -algebra on a Hilbert space when no unit equation is required.

Statement

Let be a complex -algebra considered without assuming a unit, and let be a complex Hilbert space. NonUnitalCStarRepresentation A H is the type of -representations for which no equation involving a unit is required.

Definition

For and , such a map satisfies Each is a bounded complex-linear operator. Nonzero action, irreducibility, injectivity and unit preservation are separate conditions in later declarations.

Assumptions

The Hilbert space is complete. Neither nor is required to be separable or nonzero. A unital algebra is allowed; the abbreviation merely does not require the representation to preserve its unit.

Conclusion

The result is a type of -representations, not a theorem asserting that a chosen representation is nonzero, irreducible or faithful.

Main citations

Lean source signature (exact)

The complete declaration below is a separate exact source excerpt; the original header record is retained with the manuscript.

/-- A representation of a possibly genuinely nonunital complex C-star
algebra. -/
abbrev NonUnitalCStarRepresentation (A : Type u)
    [NonUnitalCStarAlgebra A] (H : Type v)
    [NormedAddCommGroup H] [InnerProductSpace ℂ H] [CompleteSpace H] :=
  A →⋆ₙₐ[ℂ] (H →L[ℂ] H)
In the source Mathematical meaning
(A : Type u) [NonUnitalCStarAlgebra A] The complex -algebra , with no assumption requiring or forbidding a unit.
(H : Type v) The space on which algebra elements will act.
[NormedAddCommGroup H] [InnerProductSpace ℂ H] [CompleteSpace H] The complete complex Hilbert-space structure on .
H →L[ℂ] H The space of bounded complex-linear maps from to itself, with composition as multiplication and adjoint as star.
A →⋆ₙₐ[ℂ] (H →L[ℂ] H) The entire right-hand side: the type of -representations , with no unit-preservation field.

Exact source and proof.

Earlier published Card and PDF

Exact content identity

Declaration: MathlibAnnex.Analysis.CStarAlgebra.NonUnitalCStarRepresentation

Accepted content SHA-256: d540acbe030253d81f4fb82cc96f4c7815a17c9b722d5ebe4363a1407930e3e0

Accepted source guide SHA-256: 08c4aa46c05d4d43d72447d03b53f3e9dfc8f244ee40997d20a9c032f9cb24fc

Source commit: 437e6e46228bbb8e91211ebded349d7a30020e73

Back to top ↑