Ricerche di Matematica, 2026 (SCI-Expanded, Scopus)
In this work it is shown that, for a prime number p, a totally imprimitive group of finitary permutations on an infinite set has either a unique Sylow p-subgroup or the cardinality of its Sylow p-subgroups is equal to 2ℵ0. If in particular a Sylow p-subgroup of the group is transitive, then either the group is a p-group or the cardinality of its transitive Sylow p-subgroups is equal to 2ℵ0. It follows from this that the cardinality of the Sylow p-subgroups of the finitary symmetric group on a infinite set is equal to 2ℵ0.