Schematic diagrams of the mini-filament eruption in which internal reconnection (a) first occurs, followed by the external reconnection (b). The white and black blocks represent positive and negative polarities, respectively. The long yellow lines indicate nearby ambient field lines. The thick curve in light blue denotes the erupting mini-filament, and the thin lines in dark blue surrounding the mini-filament indicate the field line above (top) and the winding of the flux rope (bottom). The red stars mark the reconnection sites. The red lines show the post-flare loops, and the dashed lines indicate the ribbons. In the zoom-in panel, the dashed red lines show newly formed field lines.