Proposition 3.3 on all equal diagonal grids #
Here N=n+1 is any positive integer and Delta=I_N/N. This removes the dyadic restriction for rho and tau and adds deterministic xi and tail values.
noncomputable def
Papers.Rockel2025Approximation.equalGrid
(n : ℕ)
(C : ProbabilityTheory.Copula 2)
:
Equations
Instances For
theorem
Papers.Rockel2025Approximation.equalGrid_cdf
(n : ℕ)
(C : ProbabilityTheory.Copula 2)
(u v : ↑unitInterval)
:
(equalGrid (n + 1) C).cdf ![u, v] = 1 / (↑n + 2) * C.cdf
![ProbabilityTheory.Copula.OrdinalSum.lowerCoord (Verification.equalSplit n) u, ProbabilityTheory.Copula.OrdinalSum.lowerCoord (Verification.equalSplit n) v] + (1 - 1 / (↑n + 2)) * (equalGrid n C).cdf
![ProbabilityTheory.Copula.OrdinalSum.upperCoord (Verification.equalSplit n) u, ProbabilityTheory.Copula.OrdinalSum.upperCoord (Verification.equalSplit n) v]
theorem
Papers.Rockel2025Approximation.equalGrid_rho_tau
(n : ℕ)
(C : ProbabilityTheory.Copula 2)
:
(equalGrid n C).spearmanRho = 1 - (1 - C.spearmanRho) / (↑n + 1) ^ 2 ∧ (equalGrid n C).kendallTau = 1 - (1 - C.kendallTau) / (↑n + 1)
theorem
Papers.Rockel2025Approximation.equal_checkerboard_rho_tau
(n : ℕ)
:
(equalGrid n (ProbabilityTheory.Copula.independence 2)).spearmanRho = 1 - 1 / (↑n + 1) ^ 2 ∧ (equalGrid n (ProbabilityTheory.Copula.independence 2)).kendallTau = 1 - 1 / (↑n + 1)
theorem
Papers.Rockel2025Approximation.equal_checkMin_coefficients
(n : ℕ)
:
(equalGrid n (ProbabilityTheory.Copula.comonotonic 2)).spearmanRho = (equalGrid n (ProbabilityTheory.Copula.independence 2)).spearmanRho + 1 / (↑n + 1) ^ 2 ∧ (equalGrid n (ProbabilityTheory.Copula.comonotonic 2)).kendallTau = (equalGrid n (ProbabilityTheory.Copula.independence 2)).kendallTau + 1 / (↑n + 1) ∧ (equalGrid n (ProbabilityTheory.Copula.comonotonic 2)).chatterjeeXi = 1
theorem
Papers.Rockel2025Approximation.equal_checkW_coefficients
(n : ℕ)
:
(equalGrid n ProbabilityTheory.Copula.countermonotonic).spearmanRho = (equalGrid n (ProbabilityTheory.Copula.independence 2)).spearmanRho - 1 / (↑n + 1) ^ 2 ∧ (equalGrid n ProbabilityTheory.Copula.countermonotonic).kendallTau = (equalGrid n (ProbabilityTheory.Copula.independence 2)).kendallTau - 1 / (↑n + 1) ∧ (equalGrid n ProbabilityTheory.Copula.countermonotonic).chatterjeeXi = 1