θm=(1-ⅇ2⁢π⁢ⅈ⁢γ)⁢(1-ⅇ2⁢π⁢ⅈ⁢δ)⁢ζγ⁢(1-ζ)δ⁢(ζ-a)ϵ⁢f0⁡(q,ζ)f1⁡(q,ζ)⁢∂∂⁡q⁡𝒲⁡{f0⁡(q,ζ),f1⁡(q,ζ)}|q=qm,