Exponential growth: one round, phases, and the tail #
The round target E0 and the thresholds k_j are already in GrowthReal.lean. Here a single
round misses its target with probability at most Q(k) = q(k) / (1 + q(k)) (Cantelli), the
phase index is controlled by a potential on Kernel.iterate, and Lemma 19 crosses from k_J
to f n.
theorem
Epidemics.Revisited.prob_mono
{α : Type u_1}
[Fintype α]
(D : Dynamics.Distribution α)
{p q : α → Prop}
(h : ∀ (a : α), p a → q a)
:
theorem
Epidemics.Revisited.fail_prob_le
{n : ℕ}
{γlo γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
{S : Finset (Fin n)}
(hS : S.Nonempty)
(hk1 : 1 ≤ ↑S.card)
(hkf : ↑S.card ≤ fShrink a f * ↑n)
:
One round falls short of E0(|S|) with probability at most q / (1 + q).
Largest j ≤ J with k_j ≤ k, or 0 when k < k_0.
Equations
- Epidemics.Revisited.phaseIdx γlo γ a b n J k = Nat.findGreatest (fun (j : ℕ) => Epidemics.Revisited.kSeq γ a b (Epidemics.Revisited.growthA γlo b) n j ≤ k) J
Instances For
Equations
- Epidemics.Revisited.connectP γlo γhi a b f = γlo * (Epidemics.Revisited.alphaSeq b γlo * Epidemics.Revisited.fShrink a f / (1 + γhi)) * ((1 - a * f) / 2)
Instances For
Equations
- Epidemics.Revisited.phaseQ γ c A k = Epidemics.Revisited.qTerm γ c A k / (1 + Epidemics.Revisited.qTerm γ c A k)
Instances For
Equations
- One or more equations did not get rendered due to their size.
Instances For
Equations
- Epidemics.Revisited.phaseG γlo γhi γ a b c f n j = ∏ i ∈ Finset.Ico j (Epidemics.Revisited.phaseCount γ a f n), Epidemics.Revisited.phaseRatio γlo γhi γ a b c n i
Instances For
theorem
Epidemics.Revisited.phaseG_succ
{γlo γhi γ a b c f : ℝ}
{n j : ℕ}
(hj : j < phaseCount γ a f n)
:
theorem
Epidemics.Revisited.short_prob_le
{n : ℕ}
{γlo γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
{S : Finset (Fin n)}
(hk1 : 1 ≤ ↑S.card)
(hkf : ↑S.card ≤ fShrink a f * ↑n)
{j : ℕ}
(hj : j < phaseCount γ a f n)
(hkj : kSeq γ a b (growthA γlo b) n j ≤ ↑S.card)
:
theorem
Epidemics.Revisited.phasePot_mix
{γlo γhi γ a b c f : ℝ}
{n : ℕ}
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
{j : ℕ}
(hj : j < phaseCount γ a f n)
{T : Finset (Fin n)}
(hkj : kSeq γ a b (growthA γlo b) n j ≤ ↑T.card)
:
theorem
Epidemics.Revisited.expect_phase_le
{n : ℕ}
{γlo γhi γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
{S : Finset (Fin n)}
(hk1 : 1 ≤ ↑S.card)
(hj : phaseIdx γlo γ a b n (phaseCount γ a f n) ↑S.card < phaseCount γ a f n)
:
theorem
Epidemics.Revisited.below_le_phaseG
{γlo γhi γ a b c f : ℝ}
{n : ℕ}
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
{S : Finset (Fin n)}
(hk : 1 ≤ ↑S.card)
:
below (kSeq γ a b (growthA γlo b) n (phaseCount γ a f n)) S ≤ phaseG γlo γhi γ a b c f n (phaseIdx γlo γ a b n (phaseCount γ a f n) ↑S.card)
theorem
Epidemics.Revisited.iterate_below_phase_le
{n : ℕ}
{γlo γhi γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
(t : ℕ)
{S : Finset (Fin n)}
(hk : 1 ≤ ↑S.card)
:
theorem
Epidemics.Revisited.sum_phaseQ_le
{γlo γhi γ a b c f : ℝ}
{n : ℕ}
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
:
∑ i ∈ Finset.range (phaseCount γ a f n), phaseQ γ c (growthA γlo b) (kSeq γ a b (growthA γlo b) n i) ≤ tailQSum γlo γhi b c
Equations
- One or more equations did not get rendered due to their size.
Instances For
theorem
Epidemics.Revisited.phase_iterate_exp
{n : ℕ}
{γlo γhi γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
(r : ℕ)
{S : Finset (Fin n)}
(hk : 1 ≤ ↑S.card)
:
theorem
Epidemics.Revisited.inform_ge_connect
{n : ℕ}
{γlo γhi γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hf0 : 0 < f)
(haf : a * f < 1)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
{S : Finset (Fin n)}
(hℓ : ⌈kSeq γ a b (growthA γlo b) n (phaseCount γ a f n)⌉₊ ≤ S.card)
(hlt : ↑S.card < f * ↑n)
{x : Fin n}
(hx : x ∉ S)
:
Equations
- Epidemics.Revisited.decayAlpha γlo γhi a b c f = min (Real.log (Epidemics.Revisited.xDecay γlo γhi b c) / 2) (-Real.log (1 - Epidemics.Revisited.connectP γlo γhi a b f) / 2)
Instances For
Equations
- Epidemics.Revisited.tailPrefactor γlo γhi _a b c f = Epidemics.Revisited.tailProd γlo γhi b c * √(Epidemics.Revisited.xDecay γlo γhi b c) + 1 / (1 - f)
Instances For
theorem
Epidemics.Revisited.notYet_growth_le
{n : ℕ}
{γlo γhi γ a b c f : ℝ}
(P : RumorProcess n)
(hγlo : 0 < γlo)
(hγ : γlo ≤ γ)
(hγhi : γ ≤ γhi)
(ha : 0 ≤ a)
(hb : 0 ≤ b)
(hc : 0 ≤ c)
(hf0 : 0 < f)
(hf1 : f < 1)
(haf : a * f < 1)
(hn : growthN a b f ≤ n)
(hUG : P.UpperGrowth γ a b c f)
{S : Finset (Fin n)}
(hk : 1 ≤ ↑S.card)
(r : ℕ)
: