Decision boundaries defined by the QDA classifier based on the pEW measurements for SN II and IIb pEW are shown across three time intervals: 0–10 days (left), 10–20 days (middle) and 0–40 days after the explosion (right). The red region corresponds to predictions for SNe II, while the blue region represents SNe IIb. The decision regions with a filled contour indicate where the model assigns a given SN type. Black contour lines represent classification probability thresholds, with a solid line marking a 50% probability, dashed lines for 75%, and a dotted line for 90% of belonging to a specific class.