GeneralLinearGroup.lean`

Explanation legend Lean4 Domain Explanation Language (L4DEL)

L4DEL explanations are a separate layer. They do not change the Lean source. Intuition is explanatory prose; numbered items are a reading path; sources link the wording back to evidence.

L4DEL: Lean4 Domain Explanation Language

Annotation provenance. This overlay contains 10 curated AI-written annotations and 7190 mechanical source-derived annotations. They have not been human-reviewed as explanations; treat them as unverified and not mathematical authority. Retained generation history: The 71 original curated annotations were produced in a Claude Sonnet 5.5 session at medium effort; Claude Opus 5.5 is recorded in that session as the advisor model, not the direct author. The bulk source-derived expansion was generated mechanically from pinned source comments by tooling developed in a GPT-5.6 Sol session at ultra reasoning; GPT-5.6 Sol did not originate the quoted source prose. On 2026-10-17 the mechanically generated source-comment annotations of the Formal Conjectures, Carleson, FLT, PFR, CompFiles, Mathematics in Lean and Theorem Proving in Lean overlays were regenerated by the same generator after three corrections made in a Claude Sonnet 5.5 session: titles no longer cut a sentence inside mathematics or end on a dangling word, workflow markers are removed from the quoted prose, and declaration names follow the scanner's namespace resolution. The boilerplate step line was dropped, and comments that were only a row of dashes no longer yield annotations. No new prose was written and no human review is claimed.

Credit: The upstream authors and contributors retain credit for the project and mathematics. lean4-explainer only renders their pinned source and adds the separately disclosed explanation layer.

Project sources: Pinned project documentation, Formal Conjectures paper, arXiv v1

2 declarations, 0 contain sorry, 0 declared as axioms

Imports (1)

Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Defs

Imported by 2 files

def Matrix.GeneralLinearGroup.diagonalHom The multiplicative group homomorphism (Rˣ)ⁿ →* GL(n, R) given by mapping a vector x to Matrix.diagonal x line 29 source
Source documentation
The multiplicative group homomorphism (Rˣ)ⁿ →* GL(n, R) given by mapping a vector x to Matrix.diagonal x.

standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: DecidableEq, Fintype, CommRing, MonoidHom, Units, Matrix.GeneralLinearGroup, Matrix
Proof uses: MonoidHom.mk, OneHom.mk, Units.mk, Matrix.diagonal, Units.inv
22 instances, coercions and auxiliary constants left out.

Tactic trace: 6 steps
Open to load the checked before-and-after goal states.
```
def Matrix.GeneralLinearGroup.diagonalHom : (n → Rˣ) →* GeneralLinearGroup n R where
…
```
def Matrix.GeneralLinearGroup.diagonalSubgroup The group of invertible diagonal matrices line 35 source
Source documentation
The group of invertible diagonal matrices.

standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: DecidableEq, Fintype, CommRing, Subgroup, Matrix.GeneralLinearGroup, Matrix
Proof uses: Subgroup.map, Units, Matrix.GeneralLinearGroup.diagonalHom, Top.top
12 instances, coercions and auxiliary constants left out.
```
def Matrix.GeneralLinearGroup.diagonalSubgroup : Subgroup (GeneralLinearGroup n R) :=
…
```