Alphabeta Math

Dual Spaces Adjoint Operators and Annihilators

About this page
Pipeline-generated
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

✓ 3 results · all verified · 0 also independently AI-judged
Every result on this page is machine-checked by a proof checker and read in full by a delegated reviewing agent on the owner's instruction; the judge is an additional, independent cross-model AI review of the proofs. The 3 not AI-judged were verified by owner audit (typically over a confirmed judge false positive), not failures.
1 · Prerequisites
2 · Logical flowchart

3 · Items

Remark

The continuous dual, its completeness, and evaluation

Definition

Annihilator notation and the preannihilator

Lemma

Annihilators and preannihilators are norm closed

Theorem

The dual of a quotient is its annihilator

Theorem

The dual of a closed subspace is a dual quotient

Corollary

Distance to an annihilator is the restriction norm

Definition

The transpose of a bounded operator

Lemma

The transpose is bounded with the same norm

Lemma

Transposition reverses composition

Lemma

Elementary kernel and range annihilator identities

Corollary

Dense range is equivalent to injectivity of the transpose

Definition

The canonical evaluation map into the bidual

Theorem

The canonical bidual map is an isometry

Corollary

Distance to a closed subspace via unit annihilators

Lemma

The canonical map is natural

Definition

Reflexivity is surjectivity of the canonical map

Lemma

Membership in the transpose range by an operator estimate

Lemma

Closed range is equivalent to a quotient estimate

Lemma

A lower bound for the transpose forces a dense image of a ball

Theorem

Surjectivity is equivalent to a lower bound for the transpose

Theorem

Banach closed-range theorem

Theorem

Bounded below is equivalent to surjectivity of the transpose

Corollary

Invertibility and the inverse of the transpose

Lemma

Finite truncations approximate null and summable sequences

Theorem

The continuous dual of c0 is ell-one

Theorem

The complex continuous dual of ell-one is ell-infinity

Remark

The published Lp duality theorem in abstract notation

Definition

The weak-star topology from finite evaluations

Lemma

Finite evaluations separate a functional from a dual subspace

Theorem

Double annihilators give norm and weak-star closures

Theorem

Kernel-range identities and the weak-star closure of the transpose range

Sources