Alphabeta Math
CorollaryStatement: AI-adaptedProof: AI-generatedprecheck pass
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.

Cauchy-Schwarz inequality for L2

Statement

If f,g∈L2(μ), then

∫∣fg∣ dμ≤∥f∥2∥g∥2.

Equality holds if and only if at least one of f,g is zero almost everywhere, or there is a constant c>0 with

∣f∣2=c ∣g∣2μ-almost everywhere.

Facts & Assumptions

Given: Functions f,g∈L2(μ).

[L1]

Holder's inequality holds for conjugate exponents (Holder's inequality for integrals, including the endpoint cases).

[L2]

The strict-exponent equality criterion for Holder has already been proved (Equality in Holder's inequality for 1<p<∞).

Proof

technique · Specialize Holder to $p=q=2$, and inherit the equality clause from the strict-exponent equality theorem
1.1L1

The exponent 2 is conjugate to itself, so Holder’s inequality with p=q=2 gives ∫∣fg∣ dμ≤∥f∥2∥g∥2.

2.1L2step 1.1∎

Because 2>1, the strict-exponent equality criterion at p=q=2 says that equality in step 1.1 holds exactly when at least one of f,g is zero almost everywhere, or ∣f∣2=c∣g∣2 almost everywhere for some constant c>0. These are precisely the alternatives in the Statement.

Depends on

Dependency tree · 2 levels

Sources