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feat(QuantumMechanics): Add LinearPMap.compRestricted#1127

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jstoobysmith merged 8 commits into
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gloges:composition
May 27, 2026
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feat(QuantumMechanics): Add LinearPMap.compRestricted#1127
jstoobysmith merged 8 commits into
leanprover-community:masterfrom
gloges:composition

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@gloges gloges commented May 26, 2026

The composition of two partial linear maps, g.comp f, requires a proof that the range of f is contained in the domain of g. This PR defines g.compRestricted f (g ∘ᵣ f) which automatically restricts the domain of f to those x for which g (f x) is defined.
Also includes:

  • Some lemmas on the domain of g ∘ᵣ f and the relationship between g ∘ᵣ f and other compositions of g with f.
  • The inequality U† ∘ᵣ V† ≤ (V ∘ᵣ U)†. (The same inequality but with ∘ᵣ replaced by any composition on either side follows immediately from this, comp_le_compRestricted and adjoint_antitone.)
  • If T is symmetric then so too is T ∘ᵣ T.
  • For multiplication operators, 𝓜 f ∘ᵣ 𝓜 g ≤ 𝓜 (f • g) with equality when 𝓜 g is bounded.

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gloges commented May 26, 2026

t-quantum-mechanics

@github-actions github-actions Bot added the t-quantum-mechanics Quantum mechanics label May 26, 2026
adjoint_isFormalAdjoint h₁ ⟨u, u.2.1⟩ ⟨w, w.2.1⟩,
adjoint_isFormalAdjoint h₂ ⟨u, u.2.2⟩ ⟨w, w.2.2⟩]

lemma adjoint_comp_le_comp_adjoint [CompleteSpace H] [CompleteSpace H']
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should this be compRestricted not comp in the name?

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Thanks, I've fixed this and three other lemma names.

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Looks good to me. Will merge once linters finish

@jstoobysmith jstoobysmith added the ready-to-merge This PR is approved and will be merged shortly label May 27, 2026
@jstoobysmith jstoobysmith merged commit 696e55b into leanprover-community:master May 27, 2026
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@gloges gloges deleted the composition branch May 27, 2026 23:19
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ready-to-merge This PR is approved and will be merged shortly t-quantum-mechanics Quantum mechanics

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