2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/229047Two constructed prime number subsets (called prime brother & sisters and prime cousins) lead to a third one (called isolated primes) so that all three disjoint subsets together generate the prime number set. It should be suggested how the subset of isolated primes give a new approach to expand the set theory by using virtual subsets.13 pagesGeneral Mathematics03C55text