u}^{(-\alpha, -\beta)}\\ &= \sum_{\nu} (\alpha + \beta)^{|\nu/\lambda| - c(\nu/\lambda)} \alpha^{c(\nu/\lambda) - k}\binom{c(\nu/\lambda)}{k}\sum_{\mu/\nu \text{ vert. strip}} G_{\mu}^{(-\alpha, -\beta)} (-\alpha)^{c(\mu/\nu)}