Yang's conjecture on coincident Einstein–Bogomol'nyi strings

Let $D$ be the divisor encoding the zeros of the Higgs field $\phi$ on ${\mathbb P}^1$, and let $N$ be the total number of strings. The case in which all strings are superimposed at a single point is $D=Np$ for some point $p\in{\mathbb P}^1$.

Yang's conjecture. There is no solution of the Einstein--Bogomol'nyi equations when

$$D=Np.$$

This conjecture concerns the exceptional coincident-string configuration. The paper explains that the corresponding divisor is a borderline, strictly polystable case; the supplied text does not state that the conjecture has been resolved.