On Degeneration of the Surface in the Fitting Compactification of Moduli of Stable Vector Bundles

A new compactification of the moduli scheme of Gieseker-stable vector bundles with given Hilbert polynomial on a smooth projective polarized surface $(S,\mathsf{H})$ over a field $k=\overline k$ of zero characteristic was constructed in previous papers by the author. Families of locally free sheaves on the surface $S$ are completed by the locally free sheaves on the schemes which are certain modifications of $S$. We describe the class of modified surfaces that appear in the construction.