QIQTH.Spectral.PVM
← all sections · ← RicciSymm · SpectralTheorem →
Spectral · entries 586–669 of 1000
Lemma 586 (ProjectionValuedMeasure). source ↗
A projection-valued measure on a measurable space Ω acting on H: laws on measurable sets, with strong-operator countable additivity. This is the corrected primitive (cf. PVContent): on it the scalar measures μ_x are genuine finite measures and the Phase-1 analytic targets are sound.
hasSum_iUnion states σ-additivity vectorwise/strongly — HasSum in H, not in H →L[ℂ] H (operator-norm σ-additivity is false).
Proof. Immediate from the definitions.
Used by mk, E, isSA, isIdem, E_univ, E_inter, adjoint_eq, E_apply_idem, and 70 more.
Lemma 587 (mk). source ↗
Proof. Immediate from the definitions.
Used by PVM_of_selfAdjoint.
Definition 588 (E). source ↗
Used by rvdSpecMeasure_zero_levelSet, rvdSpecMeasure_two_levelSet, isSA, isIdem, E_univ, E_inter, adjoint_eq, E_apply_idem, and 21 more.
Lemma 589 (isSA). source ↗
Proof. Immediate from the definitions.
Used by adjoint_eq.
Lemma 590 (isIdem). source ↗
Proof. Immediate from the definitions.
Used by E_apply_idem.
Lemma 591 (E_univ). source ↗
Proof. Immediate from the definitions.
Used by scalarMeasure_univ.
Lemma 592 (E_inter). source ↗
Proof. Immediate from the definitions.
Used by integralSimple_mul_eq.
Lemma 593 (adjoint_eq). source ↗
Proof. By isSA.
Used by inner_E_self.
Lemma 594 (E_apply_idem). source ↗
Proof. By isIdem.
Used by inner_E_self.
Lemma 595 (inner_E_self). source ↗
⟪x, E s x⟫ = ‖E s x‖² for measurable s.
Proof. By adjoint_eq, E_apply_idem.
Used by diagInt_indicator_eq_inner.
Definition 596 (scalarMeasure). source ↗
The scalar spectral measure μ_x — now a genuine MeasureTheory.Measure Ω (this is Phase-1 target T1, PROVED): the strong- operator σ-additivity of E (hasSum_iUnion) pushed through the bounded linear functional ⟪x,·⟫ gives σ-additivity of s ↦ ‖E s x‖².
Used by rvdSpecMeasure, borelFC_inner_self, rvdSpec_borelFC_diag, rvdSpecMeasure_zero_levelSet, rvdSpecMeasure_two_levelSet, tendsto_integral_devChar_remainder_sq, tendsto_integral_devChar_diff_sq, scalarMeasure_apply, and 23 more.
Lemma 597 (scalarMeasure_apply). source ↗
Value of the scalar spectral measure on a measurable set.
Proof. Immediate from the definitions.
Used by rvdSpecMeasure_zero_levelSet, rvdSpecMeasure_two_levelSet, scalarMeasure_univ, scalarMeasure_toReal, scalarMeasure_smul, scalarMeasure_parallelogram_measure, scalarMeasure_odd_measure, scalarMeasure_eq_specMeasure.
Lemma 598 (scalarMeasure_univ). source ↗
Total mass ‖x‖² — μ_x is a finite measure summing the resolution of identity.
Proof. By E, E_univ, scalarMeasure_apply.
Used by instIsFiniteMeasure_scalarMeasure, diagInt_norm_le, diagInt_const.
Definition 599 (integralSimple). source ↗
Spectral integral of a simple function on the genuine PVM: ∫(∑ᵢ cᵢ 𝟙_{sᵢ}) dE = ∑ᵢ cᵢ E sᵢ.
Used by inner_integralSimple_left, boundedFC_eq_integralSimple, integralSimple_mul_eq, integralSimple_product_eq, boundedFC_simple_mul, boundedFC_simpleFunc, boundedFC_simpleFunc_mul.
Lemma 600 (inner_integralSimple_left). source ↗
Sesquilinear form of the simple integral (pure linearity, no measurability needed): ⟪x, (∫f dE) y⟫ = ∑ᵢ cᵢ ⟪x, E sᵢ y⟫. This is the bilinear datum whose diagonal is ∫ f dμ_x and whose polarization gives the complex measures μ_{x,y}.
Proof. Immediate from the definitions.
Used by boundedFC_eq_integralSimple.
Lemma 601 (scalarMeasure_toReal). source ↗
The real value of μ_x on a measurable set: (μ_x s).toReal = ‖E s x‖².
Proof. By scalarMeasure_apply.
Used by diagInt_indicator_eq_inner.
Lemma 602 (instIsFiniteMeasure_scalarMeasure). source ↗
μ_x is a finite measure (total mass ‖x‖²) — so every bounded measurable function is Bochner-integrable against it. Prerequisite for the integral functional f ↦ ∫ f dμ_x of the bounded-Borel FC.
Proof. By scalarMeasure_univ.
Used by tendsto_integral_devChar_remainder_sq, tendsto_integral_devChar_diff_sq, integrable_boundedMeasurable, diagInt_norm_le, tendsto_diagInt_of_dominated.
Lemma 603 (scalarMeasure_smul). source ↗
Scaling at the measure level: μ_{c·x} = ‖c‖² · μ_x. (E s (c•x) = c•E s x so ‖E s (c•x)‖² = ‖c‖²‖E s x‖².)
Proof. By E, scalarMeasure_apply.
Used by diagInt_smul.
Lemma 604 (scalarMeasure_parallelogram_measure). source ↗
Parallelogram at the measure level: μ_{x+y} + μ_{x−y} = 2·μ_x + 2·μ_y.
Proof. By E, scalarMeasure_apply.
Used by diagInt_parallelogram.
Lemma 605 (integrable_boundedMeasurable). source ↗
A bounded measurable function is Bochner-integrable against the finite measure μ_x.
Proof. By instIsFiniteMeasure_scalarMeasure.
Used by diagInt_parallelogram, diagInt_odd, diagInt_norm_le, diagInt_add, boundedFC_eq_integralSimple.
Definition 606 (diagInt). source ↗
The diagonal functional D_f(x) := ∫ f dμ_x (E2a of the bounded-Borel FC sub-plan). Its homogeneity D_f(c·x) = ‖c‖² D_f(x) and parallelogram law are what make the polarized form B_f(x,y) sesquilinear.
Used by borelFC_inner_self, rvdSpec_borelFC_diag, diagInt_smul, diagInt_parallelogram, bilinDiag, bilinDiag_add_left, diagInt_unit_smul, diagInt_neg, and 26 more.
Lemma 607 (diagInt_smul). source ↗
Homogeneity of the diagonal functional: D_f(c·x) = ‖c‖² D_f(x).
Proof. By scalarMeasure, scalarMeasure_smul.
Used by diagInt_unit_smul.
Lemma 608 (diagInt_parallelogram). source ↗
Parallelogram law for the diagonal functional: D_f(x+y) + D_f(x−y) = 2 D_f(x) + 2 D_f(y).
Proof. By scalarMeasure, scalarMeasure_parallelogram_measure, integrable_boundedMeasurable.
Used by bilinDiag_add_left.
Definition 609 (bilinDiag). source ↗
E2b — the polarized sesquilinear form B_f(x,y), mirroring Mathlib’s Fréchet–von Neumann–Jordan inner_ but with the quadratic functional D_f = diagInt f in place of ‖·‖². Its diagonal is D_f and (once shown sesquilinear + bounded) it represents ∫ f dE via continuousLinearMapOfBilin.
Used by borelFC_inner_self, rvdSpec_borelFC_diag, bilinDiag_add_left, bilinDiag_conj_symm, bilinDiag_add_right, bilinDiag_I_smul_left, bilinDiag_real_smul_left_nonneg, bilinDiag_zero_left, and 28 more.
Lemma 610 (bilinDiag_add_left). source ↗
Additivity in the first slot of B_f — the Jordan–von Neumann core, ported from InnerProductSpace.OfNorm.add_left (no algebraMap casting needed since D_f is already ℂ-valued), using diagInt_parallelogram.
Proof. By diagInt, diagInt_parallelogram.
Used by bilinDiag_add_right, bilinDiag_neg_left, bilinDiag_smul_left, bilinDiagₗ.
Lemma 611 (diagInt_unit_smul). source ↗
D_f is invariant under unit-modulus scaling: D_f(c·x) = D_f(x) when ‖c‖ = 1 (special case of diagInt_smul).
Proof. By diagInt_smul.
Used by diagInt_neg, diagInt_I_left, diagInt_I_right.
Lemma 612 (diagInt_neg). source ↗
D_f is even: D_f(-x) = D_f(x).
Proof. By diagInt_unit_smul.
Used by diagInt_I_left, bilinDiag_conj_symm, bilinDiag_I_smul_left, bilinDiag_zero_left.
Lemma 613 (diagInt_conj). source ↗
Conjugation passes through D_f: conj (D_f x) = D_{f̄}(x) (the scalar measure μ_x is real, so conj ∫ f = ∫ conj f).
Proof. By scalarMeasure.
Used by bilinDiag_conj_symm.
Lemma 614 (diagInt_I_left). source ↗
D_f(i·y + x) = D_f(i·x − y) (unit-scaling invariance + evenness; used to establish the conjugate-symmetry of B_f).
Proof. By diagInt_unit_smul, diagInt_neg.
Used by bilinDiag_conj_symm.
Lemma 615 (diagInt_I_right). source ↗
D_f(i·y − x) = D_f(i·x + y) (companion of diagInt_I_left).
Proof. By diagInt_unit_smul.
Used by bilinDiag_conj_symm.
Lemma 616 (bilinDiag_conj_symm). source ↗
Conjugate-symmetry of the polarized form for complex f: conj (B_f(y,x)) = B_{f̄}(x,y) where f̄ = conj ∘ f. (For real f this is the usual ⟪x,y⟫ = conj⟪y,x⟫.) This transfers slot-1 additivity to slot 2.
Proof. By diagInt, diagInt_neg, diagInt_conj, diagInt_I_left, diagInt_I_right.
Used by bilinDiag_add_right, bilinDiag_smul_right, borelFC_adjoint.
Lemma 617 (bilinDiag_add_right). source ↗
Additivity in the second slot of B_f, from slot-1 additivity (of f̄) through bilinDiag_conj_symm.
Proof. By bilinDiag_add_left, bilinDiag_conj_symm.
Used by bilinDiagₗ.
Lemma 618 (bilinDiag_I_smul_left). source ↗
i-scaling in the first slot (the I_prop of Jordan–von Neumann, pure algebra via i² = −1 and evenness of D_f): B_f(i·x, y) = conj(i)·B_f(x,y).
Proof. By diagInt, diagInt_neg.
Used by bilinDiag_smul_left.
Lemma 619 (scalarMeasure_odd_measure). source ↗
Odd measure identity (the continuity-free key to real homogeneity): for r ≥ 0, μ_{r·x+y} + r·μ_{x−y} = μ_{r·x−y} + r·μ_{x+y} (both sides equal r²‖Ex‖² + ‖Ey‖² + r‖Ex‖² + r‖Ey‖² at each set; all positive measures, no signed-measure machinery).
Proof. By E, scalarMeasure_apply.
Used by diagInt_odd.
Lemma 620 (diagInt_odd). source ↗
Odd functional identity: D_f(r·x+y) − D_f(r·x−y) = r(D_f(x+y) − D_f(x−y)) (here as D_f(r·x+y) + r·D_f(x−y) = D_f(r·x−y) + r·D_f(x+y)), r ≥ 0. Integrates scalarMeasure_odd_measure; the seed of real homogeneity of B_f.
Proof. By scalarMeasure, integrable_boundedMeasurable, scalarMeasure_odd_measure.
Used by bilinDiag_real_smul_left_nonneg.
Lemma 621 (bilinDiag_real_smul_left_nonneg). source ↗
Real homogeneity in the first slot, r ≥ 0: B_f(r·x, y) = r·B_f(x,y). Both the x and the i·x odd identities feed in; no continuity used.
Proof. By diagInt, diagInt_odd.
Used by bilinDiag_real_smul_left.
Lemma 622 (bilinDiag_zero_left). source ↗
B_f(0, y) = 0.
Proof. By diagInt, diagInt_neg.
Used by bilinDiag_neg_left, bilinDiag_norm_le.
Lemma 623 (bilinDiag_neg_left). source ↗
B_f(-x, y) = -B_f(x, y) (from additivity in the first slot).
Proof. By bilinDiag_add_left, bilinDiag_zero_left.
Used by bilinDiag_real_smul_left.
Lemma 624 (bilinDiag_real_smul_left). source ↗
Real homogeneity in the first slot (all r : ℝ): B_f(r·x,y) = r·B_f(x,y).
Proof. By bilinDiag_real_smul_left_nonneg, bilinDiag_neg_left.
Used by bilinDiag_smul_left.
Lemma 625 (bilinDiag_smul_left). source ↗
Conjugate-linearity in the first slot (full ℂ): B_f(c·x, y) = conj(c)·B_f(x,y) — combines real homogeneity, i-scaling and additivity via c = c.re + c.im·i. This is the sesquilinear half (with bilinDiag_conj_symm giving linearity in the second slot).
Proof. By bilinDiag_add_left, bilinDiag_I_smul_left, bilinDiag_real_smul_left.
Used by bilinDiag_smul_right, bilinDiag_norm_le.
Lemma 626 (diagInt_norm_le). source ↗
Diagonal bound ‖D_f x‖ ≤ C‖x‖² from ‖f‖ ≤ C and μ_x(univ) = ‖x‖².
Proof. By scalarMeasure, scalarMeasure_univ, instIsFiniteMeasure_scalarMeasure, integrable_boundedMeasurable.
Used by bilinDiag_norm_le_add.
Lemma 627 (bilinDiag_smul_right). source ↗
Linearity in the second slot: B_f(x, c·y) = c·B_f(x,y) (from conjugate-symmetry + first-slot conjugate-linearity of f̄).
Proof. By bilinDiag_conj_symm, bilinDiag_smul_left.
Used by bilinDiag_norm_le.
Lemma 628 (bilinDiag_zero_right). source ↗
B_f(x, 0) = 0.
Proof. By diagInt.
Used by bilinDiag_norm_le.
Lemma 629 (bilinDiag_norm_le_add). source ↗
Quadratic bound ‖B_f(x,y)‖ ≤ C(‖x‖²+‖y‖²) (polarization + diagonal bound + two parallelogram laws).
Proof. By diagInt, diagInt_norm_le.
Used by bilinDiag_norm_le.
Lemma 630 (bilinDiag_norm_le). source ↗
Product (bilinear) bound ‖B_f(x,y)‖ ≤ 2C·‖x‖·‖y‖ — the bound feeding LinearMap.mkContinuous₂. Proof: normalize to unit vectors and apply the quadratic bound (giving ‖u‖²+‖v‖² = 2).
Proof. By bilinDiag_zero_left, bilinDiag_smul_left, bilinDiag_smul_right, bilinDiag_zero_right, bilinDiag_norm_le_add.
Used by intBorel, inner_intBorel, intBorel_norm_le.
Definition 631 (bilinDiagₗ). source ↗
The polarized form as a bundled sesquilinear LinearMap H →ₗ⋆[ℂ] H →ₗ[ℂ] ℂ (conjugate-linear in the first slot, linear in the second), mirroring innerₛₗ.
Used by intBorel, inner_intBorel.
Definition 632 (intBorel). source ↗
The bounded-Borel functional calculus ∫ f dE (E2c), defined via the Riesz representation continuousLinearMapOfBilin of the bounded sesquilinear form B_f. Requires 0 ≤ C and ‖f‖ ≤ C.
Used by inner_intBorel, intBorel_norm_le, boundedFC, inner_boundedFC, boundedFC_norm_le.
Lemma 633 (inner_intBorel). source ↗
Defining property of ∫ f dE: ⟪(∫f dE) x, y⟫ = B_f(x,y) — the sesquilinear form B_f(x,y) = ∫ f dμ_{x,y} is realized by the operator.
Proof. By bilinDiag_norm_le, bilinDiagₗ.
Used by intBorel_norm_le, inner_boundedFC.
Lemma 634 (intBorel_norm_le). source ↗
Operator norm bound: ‖∫f dE‖ ≤ 2C. From ‖T x‖² = Re B_f(x, T x) ≤ ‖B_f(x, T x)‖ ≤ 2C‖x‖‖T x‖.
Proof. By bilinDiag, bilinDiag_norm_le, inner_intBorel.
Used by boundedFC_norm_le.
Lemma 635 (diagInt_const). source ↗
D_f of a CONSTANT function: ∫ c dμ_z = ‖z‖²·c.
Proof. By scalarMeasure, scalarMeasure_univ.
Used by bilinDiag_const.
Lemma 636 (bilinDiag_const). source ↗
B_f of a CONSTANT function is c·⟪x,y⟫ (polarization of ‖·‖² = ⟪x,y⟫). Note this is conjugate-linear in x — confirming that the Riesz operator intBorel is the conjugated calculus (see intBorel_const).
Proof. By diagInt, diagInt_const.
Used by boundedFC_const.
Definition 637 (boundedFC). source ↗
The correctly-oriented bounded-Borel functional calculus Φ(f) := (∫f dE)* (the adjoint of the Riesz operator), so that ⟪x, Φ(f) y⟫ = B_f(x,y) = ∫ f dμ_{x,y} with the operator on the SECOND slot — the standard convention.
Used by deviceOpC_norm_le, inner_boundedFC, boundedFC_const, boundedFC_add, boundedFC_smul, boundedFC_norm_le, boundedFC_congr, boundedFC_indicator, and 9 more.
Lemma 638 (inner_boundedFC). source ↗
Defining property of the oriented FC: ⟪x, Φ(f) y⟫ = B_f(x,y).
Proof. By intBorel, inner_intBorel.
Used by boundedFC_const, boundedFC_add, boundedFC_smul, boundedFC_congr, boundedFC_indicator, boundedFC_eq_integralSimple, boundedFC_mul_simpleFunc_left, boundedFC_mul, and 1 more.
Lemma 639 (boundedFC_const). source ↗
Unitality / constant rule: Φ(const c) = c·1. In particular Φ(1) = 1, so the oriented calculus is unital (a genuine functional calculus).
Proof. By bilinDiag, bilinDiag_const, inner_boundedFC.
Used by borelFC_one, borelFC_const.
Lemma 640 (diagInt_add). source ↗
Additivity of the diagonal functional in f: D_{f+g} = D_f + D_g.
Proof. By scalarMeasure, integrable_boundedMeasurable.
Used by bilinDiag_add_f.
Lemma 641 (diagInt_finsetSum). source ↗
Linearity of the diagonal functional over finite sums: D_{∑ᵢ Fᵢ} = ∑ᵢ D_{Fᵢ} (each Fᵢ integrable against μ_z). Bound-free.
Proof. Immediate from the definitions.
Used by bilinDiag_finsetSum.
Lemma 642 (bilinDiag_add_f). source ↗
Additivity of the polarized sesquilinear form in f: B_{f+g} = B_f + B_g.
Proof. By diagInt, diagInt_add.
Used by boundedFC_add.
Lemma 643 (bilinDiag_finsetSum). source ↗
Linearity of the polarized form over finite sums: B_{∑ᵢ Fᵢ} = ∑ᵢ B_{Fᵢ}.
Proof. By diagInt, diagInt_finsetSum.
Used by boundedFC_eq_integralSimple.
Lemma 644 (boundedFC_add). source ↗
Additivity of the bounded-Borel FC in f: Φ(f+g) = Φ(f) + Φ(g).
Proof. By bilinDiag, inner_boundedFC, bilinDiag_add_f.
Used by borelFC_add.
Lemma 645 (diagInt_smul_f). source ↗
Scalar-homogeneity of the diagonal functional in f: D_{c·f} = c·D_f.
Proof. By scalarMeasure.
Used by bilinDiag_smul_f.
Lemma 646 (bilinDiag_smul_f). source ↗
Scalar-homogeneity of the polarized form in f: B_{c·f} = c·B_f.
Proof. By diagInt, diagInt_smul_f.
Used by boundedFC_smul, boundedFC_eq_integralSimple.
Lemma 647 (boundedFC_smul). source ↗
ℂ-homogeneity of the bounded-Borel FC in f: Φ(c·f) = c·Φ(f).
Proof. By bilinDiag, inner_boundedFC, bilinDiag_smul_f.
Used by borelFC_smul.
Lemma 648 (boundedFC_norm_le). source ↗
Operator-norm bound for the bounded-Borel FC: ‖Φ(f)‖ ≤ 2C for ‖f‖∞ ≤ C. (Φ(f) is the adjoint of the Riesz operator intBorel f, and the adjoint is a linear isometry.) This is the estimate that makes the simple→bounded-Borel extension converge in OPERATOR NORM — the route to multiplicativity Φ(fg)=Φ(f)Φ(g) that weak-operator convergence cannot deliver.
Proof. By intBorel, intBorel_norm_le.
Used by deviceOpC_norm_le, cfcCont_norm_le.
Lemma 649 (boundedFC_congr). source ↗
Φ(f) depends only on f, not on the bound: equal functions give equal operators (the value is ⟪x,Φ(f)y⟫ = B_f(x,y), independent of the bound proof). Lets us rewrite f to any pointwise-equal form (e.g. reindex a product).
Proof. By bilinDiag, inner_boundedFC.
Used by boundedFC_simple_mul, boundedFC_simpleFunc, boundedFC_simpleFunc_mul, borelFC_congr.
Lemma 650 (norm_indicatorOne_le). source ↗
The complex indicator 𝟙_s is bounded by 1.
Proof. Immediate from the definitions.
Used by boundedFC_indicator, boundedFC_eq_integralSimple, boundedFC_simple_mul, boundedFC_simpleFunc, boundedFC_simpleFunc_mul, borelFC_indicator, rvdRC_mul_E_levelSet.
Lemma 651 (diagInt_indicator). source ↗
D_{𝟙_s}(z) = μ_z(s) — the diagonal functional of an indicator is the scalar spectral mass.
Proof. Immediate from the definitions.
Used by diagInt_indicator_eq_inner.
Lemma 652 (diagInt_indicator_eq_inner). source ↗
D_{𝟙_s}(z) = ⟪z, E s z⟫ — the diagonal of the indicator’s form is the projection’s quadratic form.
Proof. By inner_E_self, scalarMeasure, scalarMeasure_toReal, diagInt_indicator.
Used by bilinDiag_indicator.
Lemma 653 (bilinDiag_indicator). source ↗
Indicator bridge (polarized): the bounded-Borel sesquilinear form of an indicator is the spectral projection’s form, B_{𝟙_s}(x,y) = ⟪x, E s y⟫. Proved by reducing the four polarization points to ⟪z, E s z⟫ and expanding by sesquilinearity (the same Jordan–von Neumann computation as inner_E_polarization, with the I•x ± y convention of bilinDiag).
Proof. By diagInt, diagInt_indicator_eq_inner.
Used by boundedFC_indicator, boundedFC_eq_integralSimple.
Lemma 654 (boundedFC_indicator). source ↗
The bounded-Borel FC of an indicator is the spectral projection: Φ(𝟙_s) = E s. This anchors the abstract Borel functional calculus to the PVM it came from.
Proof. By bilinDiag, inner_boundedFC, bilinDiag_indicator.
Used by borelFC_indicator.
Lemma 655 (boundedFC_eq_integralSimple). source ↗
The bounded-Borel FC of a simple function is its spectral integral: Φ(∑ᵢ cᵢ 𝟙_{sᵢ}) = ∑ᵢ cᵢ E sᵢ = integralSimple. Proved at the sesquilinear-form level: B_{∑cᵢ𝟙_{sᵢ}} = ∑ cᵢ B_{𝟙_{sᵢ}} = ∑ cᵢ ⟪x, E sᵢ y⟫ (finset linearity + smul-in-f + the indicator bridge).
Proof. By E, inner_integralSimple_left, integrable_boundedMeasurable, bilinDiag, inner_boundedFC, bilinDiag_finsetSum, bilinDiag_smul_f, bilinDiag_indicator.
Used by boundedFC_simple_mul, boundedFC_simpleFunc.
Lemma 656 (integralSimple_mul_eq). source ↗
Operator product of two simple integrals (the algebraic core of multiplicativity Φ(fg)=Φ(f)Φ(g) for simple f,g): cross terms collapse by E Aᵢ · E Bⱼ = E(Aᵢ ∩ Bⱼ).
Proof. By E_inter.
Used by integralSimple_product_eq.
Lemma 657 (integralSimple_product_eq). source ↗
The simple integral over the product index t ×ˢ s (weights aᵢbⱼ, sets Aᵢ ∩ Bⱼ) equals the product of the two simple integrals. Pure operator algebra (integralSimple_mul_eq + Finset.sum_product).
Proof. By E, integralSimple_mul_eq.
Used by boundedFC_simple_mul.
Lemma 658 (boundedFC_simple_mul). source ↗
Multiplicativity on simple functions: Φ(f·g) = Φ(f)·Φ(g) for simple f = ∑ᵢ aᵢ 𝟙_{Aᵢ}, g = ∑ⱼ bⱼ 𝟙_{Bⱼ}. Stated with Φ(f), Φ(g) as the simple integrals (= Φ(f), Φ(g) by boundedFC_eq_integralSimple). Proof: the product f·g reindexes pointwise to the t ×ˢ s simple function (boundedFC_congr + Finset.sum_mul_sum + the indicator product 𝟙_A·𝟙_B = 𝟙_{A∩B}), whose FC is integralSimple (t ×ˢ s) = (integralSimple t)·(integralSimple s).
Proof. By boundedFC_congr, boundedFC_eq_integralSimple, integralSimple_product_eq.
Used by boundedFC_simpleFunc_mul.
Lemma 659 (simpleFunc_eq_sum). source ↗
SimpleFunc as a sum of scaled indicators (the bridge from Mathlib’s SimpleFunc, produced by approxOn, to the ∑ cᵢ 𝟙_{sᵢ} form of our FC lemmas): φ a = ∑_{y ∈ φ.range} y · 𝟙_{φ⁻¹{y}}(a). Exactly one range term is nonzero.
Proof. Immediate from the definitions.
Used by boundedFC_simpleFunc, boundedFC_simpleFunc_mul.
Lemma 660 (boundedFC_simpleFunc). source ↗
The FC of a SimpleFunc equals the spectral integral over its range: Φ(⇑φ) = ∑_{y ∈ φ.range} y · E(φ⁻¹{y}).
Proof. By boundedFC_congr, norm_indicatorOne_le, boundedFC_eq_integralSimple, simpleFunc_eq_sum.
Used by boundedFC_simpleFunc_mul.
Lemma 661 (boundedFC_simpleFunc_mul). source ↗
Multiplicativity on SimpleFuncs: Φ(⇑φ · ⇑ψ) = Φ(⇑φ)·Φ(⇑ψ). Reduces to boundedFC_simple_mul over the ranges of φ, ψ via simpleFunc_eq_sum.
Proof. By integralSimple, boundedFC_congr, norm_indicatorOne_le, boundedFC_simple_mul, simpleFunc_eq_sum, boundedFC_simpleFunc.
Used by boundedFC_mul_simpleFunc_left.
Lemma 662 (tendsto_diagInt_of_dominated). source ↗
Dominated/bounded convergence for the diagonal functional: if fₙ → f pointwise with a common bound C, then D_{fₙ}(z) → D_f(z). (DCT against the finite measure μ_z.) The engine for extending FC identities from simple to all bounded Borel functions.
Proof. By scalarMeasure, instIsFiniteMeasure_scalarMeasure.
Used by tendsto_bilinDiag_of_dominated.
Lemma 663 (tendsto_bilinDiag_of_dominated). source ↗
Bound-free form of the normality engine: B_{fₙ}(x,y) → B_f(x,y) under bounded pointwise convergence (the limit f needs no bound — bilinDiag carries none). This is the workhorse for the simple→bounded-Borel multiplicativity extension.
Proof. By diagInt, tendsto_diagInt_of_dominated.
Used by boundedFC_mul_simpleFunc_left, boundedFC_mul.
Definition 664 (approxSeq). source ↗
The approxOn simple-function sequence for a bounded measurable f (base point 0, set univ): approxSeq f hf n is a SimpleFunc, → f pointwise, with ‖approxSeq f hf n ω‖ ≤ 2‖f ω‖.
Used by approxSeq_tendsto, approxSeq_norm_le, approxSeq_measurable, boundedFC_mul_simpleFunc_left, boundedFC_mul.
Lemma 665 (approxSeq_tendsto). source ↗
Proof. Immediate from the definitions.
Used by boundedFC_mul_simpleFunc_left, boundedFC_mul.
Lemma 666 (approxSeq_norm_le). source ↗
Proof. Immediate from the definitions.
Used by boundedFC_mul_simpleFunc_left, boundedFC_mul.
Lemma 667 (approxSeq_measurable). source ↗
Proof. Immediate from the definitions.
Used by boundedFC_mul_simpleFunc_left, boundedFC_mul.
Lemma 668 (boundedFC_mul_simpleFunc_left). source ↗
Stage 1 (left simple): Φ(⇑φ · g) = Φ(⇑φ)·Φ(g) for a SimpleFunc φ and a bounded measurable g. Approximate g by SimpleFuncs gₘ → g and pass to the weak limit: ⟪x, Φ(φ·gₘ)y⟫ = ⟪Φ(φ)†x, Φ(gₘ)y⟫ (by boundedFC_simpleFunc_mul), both sides converge (tendsto_bilinDiag), so the limits agree.
Proof. By bilinDiag, inner_boundedFC, boundedFC_simpleFunc_mul, tendsto_bilinDiag_of_dominated, approxSeq, approxSeq_tendsto, approxSeq_norm_le, approxSeq_measurable.
Used by boundedFC_mul.
Lemma 669 (boundedFC_mul). source ↗
MULTIPLICATIVITY OF THE BOUNDED-BOREL FUNCTIONAL CALCULUS (the keystone): Φ(f·g) = Φ(f)·Φ(g) for all bounded measurable f, g. Approximate f by SimpleFuncs fₙ → f and pass to the weak limit, using Stage 1 (left-simple multiplicativity) for each fₙ: ⟪x, Φ(fₙ·g)y⟫ = ⟪x, Φ(fₙ)(Φ(g)y)⟫, both sides converge (tendsto_bilinDiag), so the limits agree. Together with boundedFC_add, boundedFC_smul and boundedFC_const, the FC Φ : Bᵇ(Ω) → (H →L[ℂ] H) is a unital *-algebra homomorphism.
Proof. By bilinDiag, inner_boundedFC, tendsto_bilinDiag_of_dominated, approxSeq, approxSeq_tendsto, approxSeq_norm_le, approxSeq_measurable, boundedFC_mul_simpleFunc_left.
Used by borelFC_mul.