Let $\varphi : = (1 + \sqrt{5}) / 2$ be the D2137: Basic real golden ratio such that
(i) | \begin{equation} \varphi_* : = 1 - \varphi \end{equation} |
Then
(1) | \begin{equation} \varphi^2 = \varphi + 1 \end{equation} |
(2) | \begin{equation} \varphi^2_* = \varphi_* + 1 \end{equation} |