Bethe equations “on the wrong side of the equator”

The $T$–$Q$ Baxter equations for the $XXX$ ($XXZ$) spin chain are analyzed. For each polynomial (trigonometric) solution of degree not exceeding $N/2$, which provides a solution of the Bethe ansatz equations, there exists a second linearly independent polynomial solution of degree greater than $N/2$. This second solution plays an essential role; in particular, all fusion relations follow from these two solutions.