[scottdhughes]

Relate the existing finite boost to its named generator: for every i : Fin 3, the underlying matrix of LorentzGroup.boost i (Real.tanh r) (Real.abs_tanh_lt_one r) has derivative -lorentzAlgebra.boostGenerator i at r = 0, with no additional hypotheses. The negative sign follows the native boost's off-diagonal entries −γ(β)β.

Add two public lemmas:

• In Physlib/Relativity/LorentzGroup/Boosts/Basic.lean, LorentzGroup.γ_tanh (r : ℝ): γ (Real.tanh r) = Real.cosh r, for every real rapidity without further hypotheses.
• In Physlib/Relativity/LorentzAlgebra/Basis.lean, lorentzAlgebra.hasDerivAt_boost_tanh_zero: the ambient real matrix derivative above. The elementary cosh r * tanh r = sinh r calculation is a local have hcosh inside its proof.

Update both modules' documentation, including the boost sign convention, and remove their two entries from scripts/lint/exemptions/module_doc_no_lint.txt. Move the Artanh import to the gamma identity's module and remove two direct imports it makes redundant.

Reviewer map: inspect the native boost and generator signs, then the public gamma identity, then the componentwise derivative proof and documentation changes.

Validation against master 4ed4eb11f943324eaa0d4e5c85fb36a8b9a47922 (Lean 4.35.0, Mathlib 56a005855ea17e0b0958f73ec801ae140b0a1679): full Physlib/QuantumInfo and explicit PhyslibAlpha builds, all direct required checks, committed-state Python style, API-map and spelling checks pass. Native-only consumer probes compile eight examples; all 15 default declaration linters pass on both public additions. Their axiom reports contain only propext, Classical.choice and Quot.sound.

Baseline exceptions, reproduced on a separate pristine checkout at that master:

• Optional style_lint exits 1 with the same four complete compiler-error blocks at lines 47, 50, 68 and 71 (Substring.Raw.findAllSubstr / stopPos).
• redundant_imports exits 0 with exactly the same 39 advisory groups, with none added, removed or changed.
• lint_all exits 0 but masks child failures; the direct results above are recorded separately.

The pristine comparison covers the default build, optional style, redundant imports and module documentation; the revision's remaining required checks were run directly. No Nanoda replay or hosted CI has been run for this revision.

Developed with OpenAI Codex assistance for proof development, implementation, documentation, validation and this description.

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For reviewers: Summary of your PR

Found differences:
@@ Physlib.Relativity.LorentzAlgebra.Basis @@
! module modified Physlib.Relativity.LorentzAlgebra.Basis (+55 -14)
  namespaces lorentzAlgebra
+ added lemma hasDerivAt_boost_tanh_zero
@@ Physlib.Relativity.LorentzGroup.Boosts.Basic @@
! module modified Physlib.Relativity.LorentzGroup.Boosts.Basic (+37 -3)
  namespaces LorentzGroup
+ added lemma γ_tanh
@@ scripts/lint/exemptions/module_doc_no_lint.txt @@
! file modified scripts/lint/exemptions/module_doc_no_lint.txt (+0 -2)
5 differences

The declarations are found by reading the diff as text, without regard for namespaces, so a declaration whose keyword and name are on different lines is missed, and two declarations of the same name in different namespaces are listed as one. A change to a proof, or to the body of a definition, does not appear. See scripts/alpha/github/pr_summary.lean.

Summary of commit efe0917, remade whenever a commit is pushed.

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[jstoobysmith]

If we can get aay without this lemma, then I think we should include it in the proof of hasDerivAt_boost_tanh_zero

[jstoobysmith]

This could be near the definition of LorentzGroup.γ and made non-private, as it seems an important result

[jstoobysmith]

Would try and put as much of this on one line as possible to clean up the text

[jstoobysmith]

awaiting-author

[scottdhughes]

-awaiting-author
t-relativity

[jstoobysmith]

Approved. Will merge now