2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/14925Criterion for the membership of individual meteors to meteoroid streams presented by Valsecchi {\it et. al.} (1999) and Jopek {\it et. al.} (1999) is discussed. The authors characterize and use their criterion as a distance function. However, it is not a distance function. Some practical aspects are also discussed. Correct criterion is presented.Astrophysicstext