InformationTheory

InformationTheory.Shannon.BroadcastChannel.Marton.Setup

source

Marton's inner bound — five-variable ambient setup #

The random-coding ensemble behind Marton's inner bound carries a pair of auxiliary variables (V₁, V₂), one per receiver, so the per-coordinate law is a quintuple (V₁, V₂, X, Y₁, Y₂) rather than the quadruple (U, X, Y₁, Y₂) of superposition coding. This file builds that law from a joint auxiliary distribution pV on V₁ × V₂, an input kernel K : Kernel (V₁ × V₂) α and a broadcast channel W, together with its i.i.d. ambient measure, the coordinate facts consumed downstream, and the three informations appearing in the region inequalities.

The input is produced by a general kernel K rather than a deterministic map x = f(v₁, v₂): a deterministic kernel puts zero mass off its image, which is incompatible with the full-support hypotheses hpV / hK / hW that every typicality bound in this development requires.

Main definitions #

Implementation notes #

The informations are entropy differences over rather than InformationTheory.Shannon.mutualInfo (valued in ℝ≥0∞), matching the form in which the typicality bounds of this development state their exponents.

Per-coordinate joint distribution #

noncomputable def

InformationTheory.Shannon.BroadcastChannel.Marton.martonJointDistribution

source
{V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [MeasurableSpace V₁] [MeasurableSpace V₂] [MeasurableSpace α] [MeasurableSpace β₁] [MeasurableSpace β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) (K : ProbabilityTheory.Kernel (V₁ × V₂) α) (W : BCChannel α β₁ β₂) :
MeasureTheory.Measure (V₁ × V₂ × α × β₁ × β₂)

The per-coordinate Marton joint law on V₁ × V₂ × α × β₁ × β₂: the compProd chain pV → K → W ((V₁, V₂) ∼ pV, X ∣ (V₁, V₂) ∼ K, (Y₁, Y₂) ∣ X ∼ W), reshaped from the left-nested ((V₁ × V₂) × α) × (β₁ × β₂) to the right-nested quintuple. Two reassociations are needed, one more than for the four-variable superposition law.

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      instance

      InformationTheory.Shannon.BroadcastChannel.Marton.martonJointDistribution.instIsProbabilityMeasure

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      Used by
        theorem

        InformationTheory.Shannon.BroadcastChannel.Marton.martonJointDistribution_map_V

        source
        {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] :
        MeasureTheory.Measure.map (fun (q : V₁ × V₂ × α × β₁ × β₂) => (q.1, q.2.1)) (martonJointDistribution pV K W) = pV
        Used by
          theorem

          InformationTheory.Shannon.BroadcastChannel.Marton.martonJointDistribution_singleton_pos

          source
          {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (hpV : ∀ (v : V₁ × V₂), 0 < pV.real {v}) (hK : ∀ (v : V₁ × V₂) (a : α), 0 < (K v).real {a}) (hW : ∀ (a : α) (b : β₁ × β₂), 0 < (W a).real {b}) (q : V₁ × V₂ × α × β₁ × β₂) :
          Used by

            I.i.d. ambient measure on ℕ → V₁ × V₂ × α × β₁ × β₂ #

            noncomputable def

            InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbientMeasure

            source
            {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [MeasurableSpace V₁] [MeasurableSpace V₂] [MeasurableSpace α] [MeasurableSpace β₁] [MeasurableSpace β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) (K : ProbabilityTheory.Kernel (V₁ × V₂) α) (W : BCChannel α β₁ β₂) :
            MeasureTheory.Measure (V₁ × V₂ × α × β₁ × β₂)

            The i.i.d. Marton ambient measure: Measure.infinitePi (fun _ => martonJointDistribution pV K W).

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                instance

                InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbientMeasure.instIsProbabilityMeasure

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                Used by
                  def

                  InformationTheory.Shannon.BroadcastChannel.Marton.martonV₁s

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                  {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} :
                  (V₁ × V₂ × α × β₁ × β₂)V₁

                  The first auxiliary coordinate ω ↦ (ω i).1.

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                      def

                      InformationTheory.Shannon.BroadcastChannel.Marton.martonV₂s

                      source
                      {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} :
                      (V₁ × V₂ × α × β₁ × β₂)V₂

                      The second auxiliary coordinate ω ↦ (ω i).2.1.

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                          def

                          InformationTheory.Shannon.BroadcastChannel.Marton.martonXs

                          source
                          {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} :
                          (V₁ × V₂ × α × β₁ × β₂)α

                          The channel input coordinate ω ↦ (ω i).2.2.1.

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                              def

                              InformationTheory.Shannon.BroadcastChannel.Marton.martonY₁s

                              source
                              {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} :
                              (V₁ × V₂ × α × β₁ × β₂)β₁

                              The first output coordinate ω ↦ (ω i).2.2.2.1.

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                              Instances For
                                Used by
                                  def

                                  InformationTheory.Shannon.BroadcastChannel.Marton.martonY₂s

                                  source
                                  {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} :
                                  (V₁ × V₂ × α × β₁ × β₂)β₂

                                  The second output coordinate ω ↦ (ω i).2.2.2.2.

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                                      Coordinate facts for the Marton ambient measure #

                                      theorem

                                      InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbient_map_coord

                                      source
                                      {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] {γ : Type u_6} [MeasurableSpace γ] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (g : V₁ × V₂ × α × β₁ × β₂γ) (hg : Measurable g) (i : ) :
                                      MeasureTheory.Measure.map (fun (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω i)) (martonAmbientMeasure pV K W) = MeasureTheory.Measure.map g (martonJointDistribution pV K W)
                                      Used by
                                        theorem

                                        InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbient_iIndepFun_coord

                                        source
                                        {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] {γ : Type u_6} [MeasurableSpace γ] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (g : V₁ × V₂ × α × β₁ × β₂γ) (hg : Measurable g) :
                                        ProbabilityTheory.iIndepFun (fun (i : ) (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω i)) (martonAmbientMeasure pV K W)
                                        Used by
                                          theorem

                                          InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbient_identDistrib_coord

                                          source
                                          {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] {γ : Type u_6} [MeasurableSpace γ] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (g : V₁ × V₂ × α × β₁ × β₂γ) (hg : Measurable g) (i : ) :
                                          ProbabilityTheory.IdentDistrib (fun (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω i)) (fun (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω 0)) (martonAmbientMeasure pV K W) (martonAmbientMeasure pV K W)
                                          Used by
                                            theorem

                                            InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbient_entropy_coord

                                            source
                                            {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] {γ : Type u_6} [Fintype γ] [Nonempty γ] [MeasurableSpace γ] [MeasurableSingletonClass γ] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (g : V₁ × V₂ × α × β₁ × β₂γ) (hg : Measurable g) (i : ) :
                                            (entropy (martonAmbientMeasure pV K W) fun (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω i)) = entropy (martonJointDistribution pV K W) g
                                            Used by
                                              theorem

                                              InformationTheory.Shannon.BroadcastChannel.Marton.martonAmbient_coord_marginal_pos

                                              source
                                              {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] {γ : Type u_6} [MeasurableSpace γ] [MeasurableSingletonClass γ] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] (hpV : ∀ (v : V₁ × V₂), 0 < pV.real {v}) (hK : ∀ (v : V₁ × V₂) (a : α), 0 < (K v).real {a}) (hW : ∀ (a : α) (b : β₁ × β₂), 0 < (W a).real {b}) (g : V₁ × V₂ × α × β₁ × β₂γ) (hg : Measurable g) (i : ) (c : γ) (r : V₁ × V₂ × α × β₁ × β₂) (hr : g r = c) :
                                              0 < (MeasureTheory.Measure.map (fun (ω : V₁ × V₂ × α × β₁ × β₂) => g (ω i)) (martonAmbientMeasure pV K W)).real {c}
                                              Used by

                                                The three informations of the region inequalities #

                                                noncomputable def

                                                InformationTheory.Shannon.BroadcastChannel.Marton.martonInfo₁

                                                source
                                                {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [MeasurableSpace V₁] [MeasurableSpace V₂] [MeasurableSpace α] [Fintype β₁] [MeasurableSpace β₁] [MeasurableSpace β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) (K : ProbabilityTheory.Kernel (V₁ × V₂) α) (W : BCChannel α β₁ β₂) :

                                                The first-receiver information I(V₁; Y₁) = H(V₁) + H(Y₁) − H(V₁, Y₁) of the per-coordinate Marton joint law.

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                                                  Used by
                                                    noncomputable def

                                                    InformationTheory.Shannon.BroadcastChannel.Marton.martonInfo₂

                                                    source
                                                    {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [MeasurableSpace V₁] [Fintype V₂] [MeasurableSpace V₂] [MeasurableSpace α] [MeasurableSpace β₁] [Fintype β₂] [MeasurableSpace β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) (K : ProbabilityTheory.Kernel (V₁ × V₂) α) (W : BCChannel α β₁ β₂) :

                                                    The second-receiver information I(V₂; Y₂) = H(V₂) + H(Y₂) − H(V₂, Y₂) of the per-coordinate Marton joint law.

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                                                      Used by
                                                        noncomputable def

                                                        InformationTheory.Shannon.BroadcastChannel.Marton.martonInfoV₁V₂

                                                        source
                                                        {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [MeasurableSpace V₁] [Fintype V₂] [MeasurableSpace V₂] [MeasurableSpace α] [MeasurableSpace β₁] [MeasurableSpace β₂] (pV : MeasureTheory.Measure (V₁ × V₂)) (K : ProbabilityTheory.Kernel (V₁ × V₂) α) (W : BCChannel α β₁ β₂) :

                                                        The auxiliary-variable dependence I(V₁; V₂) = H(V₁) + H(V₂) − H(V₁, V₂) of the per-coordinate Marton joint law. This is the penalty subtracted from the sum rate: it is the rate at which the two subcodebooks have to be over-provisioned for a jointly typical pair to exist.

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                                                          Used by
                                                            theorem

                                                            InformationTheory.Shannon.BroadcastChannel.Marton.martonInfo₁_eq_zero_of_subsingleton

                                                            source
                                                            {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] [Subsingleton V₁] (pV : MeasureTheory.Measure (V₁ × V₂)) [MeasureTheory.IsProbabilityMeasure pV] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] :
                                                            martonInfo₁ pV K W = 0
                                                            Used by
                                                              theorem

                                                              InformationTheory.Shannon.BroadcastChannel.Marton.martonInfoV₁V₂_eq_zero_of_prod

                                                              source
                                                              {V₁ : Type u_1} {V₂ : Type u_2} {α : Type u_3} {β₁ : Type u_4} {β₂ : Type u_5} [Fintype V₁] [DecidableEq V₁] [Nonempty V₁] [MeasurableSpace V₁] [MeasurableSingletonClass V₁] [Fintype V₂] [DecidableEq V₂] [Nonempty V₂] [MeasurableSpace V₂] [MeasurableSingletonClass V₂] [Fintype α] [DecidableEq α] [Nonempty α] [MeasurableSpace α] [MeasurableSingletonClass α] [Fintype β₁] [DecidableEq β₁] [Nonempty β₁] [MeasurableSpace β₁] [MeasurableSingletonClass β₁] [Fintype β₂] [DecidableEq β₂] [Nonempty β₂] [MeasurableSpace β₂] [MeasurableSingletonClass β₂] (p₁ : MeasureTheory.Measure V₁) [MeasureTheory.IsProbabilityMeasure p₁] (p₂ : MeasureTheory.Measure V₂) [MeasureTheory.IsProbabilityMeasure p₂] (K : ProbabilityTheory.Kernel (V₁ × V₂) α) [ProbabilityTheory.IsMarkovKernel K] (W : BCChannel α β₁ β₂) [ProbabilityTheory.IsMarkovKernel W] :
                                                              martonInfoV₁V₂ (p₁.prod p₂) K W = 0
                                                              Used by