theorem
Verification.studentBivariate_lowerTail_raw
{r : ℝ}
(hr : r ∈ Set.Ioo (-1) 1)
(ν : ℝ)
(hν : 0 < ν)
:
(studentBivariate r ⋯ ν hν).HasLowerTailDependence
(2 * ↑(ProbabilityTheory.cdf
(ProbabilityTheory.Copula.marginal (ProbabilityTheory.Copula.studentTLaw (bivariateCorrelation 0) (ν + 1) ⋯)
0))
(-(1 - r) / √((1 - r ^ 2) / (ν + 1))))
theorem
Verification.studentBivariate_lowerTail_interior
{r : ℝ}
(hr : r ∈ Set.Ioo (-1) 1)
(ν : ℝ)
(hν : 0 < ν)
:
(studentBivariate r ⋯ ν hν).HasLowerTailDependence
(2 - 2 * ↑(ProbabilityTheory.cdf
(ProbabilityTheory.Copula.marginal (ProbabilityTheory.Copula.studentTLaw (bivariateCorrelation 0) (ν + 1) ⋯)
0))
√((ν + 1) * (1 - r) / (1 + r)))
theorem
Verification.studentBivariate_upperTail_interior
{r : ℝ}
(hr : r ∈ Set.Ioo (-1) 1)
(ν : ℝ)
(hν : 0 < ν)
:
(studentBivariate r ⋯ ν hν).HasUpperTailDependence
(2 - 2 * ↑(ProbabilityTheory.cdf
(ProbabilityTheory.Copula.marginal (ProbabilityTheory.Copula.studentTLaw (bivariateCorrelation 0) (ν + 1) ⋯)
0))
√((ν + 1) * (1 - r) / (1 + r)))
theorem
Verification.studentBivariate_lowerTail
{r : ℝ}
(hr : r ∈ Set.Icc (-1) 1)
(ν : ℝ)
(hν : 0 < ν)
:
(studentBivariate r hr ν hν).HasLowerTailDependence
(if r = 1 then 1
else if r = -1 then 0
else 2 - 2 * ↑(ProbabilityTheory.cdf
(ProbabilityTheory.Copula.marginal
(ProbabilityTheory.Copula.studentTLaw (bivariateCorrelation 0) (ν + 1) ⋯) 0))
√((ν + 1) * (1 - r) / (1 + r)))
theorem
Verification.studentBivariate_upperTail
{r : ℝ}
(hr : r ∈ Set.Icc (-1) 1)
(ν : ℝ)
(hν : 0 < ν)
:
(studentBivariate r hr ν hν).HasUpperTailDependence
(if r = 1 then 1
else if r = -1 then 0
else 2 - 2 * ↑(ProbabilityTheory.cdf
(ProbabilityTheory.Copula.marginal
(ProbabilityTheory.Copula.studentTLaw (bivariateCorrelation 0) (ν + 1) ⋯) 0))
√((ν + 1) * (1 - r) / (1 + r)))