Alphabeta Math
CorollaryStatement: AI-adaptedProof: AI-adaptedSession-authored (Fable 5 assisted)precheck passaudited 2026-08-28
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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.

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The operator norm is submultiplicative and satisfies ||T^*T|| = ||T||^2

Statement

For compatible linear maps between finite-dimensional real or complex inner product spaces,

STST.

For every such linear map T,

TT=T2.

Facts & Assumptions

Given: Compatible finite-dimensional linear maps T and S between real or complex inner product spaces.

[L1]

The operator norm is defined by the maximum over unit vectors (The operator norm is zero on the zero domain and otherwise is max_{||v||=1} ||Tv||).

[L3]

If Tej=sjej is a singular value decomposition, then TTej=sj2ej (Every linear map between finite-dimensional real or complex inner product spaces admits a singular value decomposition).

Proof

technique · direct
1.1

For every unit vector v in the domain of T, [L1] gives STvSTvST. Taking the maximum over all unit v yields STST.

L1algebra
2.1

If s1s2 are the singular values of T, then [L3] shows that TT has eigenvalues s12,s22, and is already non-negative. Hence its singular values are s12,s22,, so [L2] gives TT=s12=T2.

L2L3algebra

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · two levels

8 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.

Sources