A note on the rationality of Sylow 2-subgroups of rational groups

Resumo

A finite group whose all irreducible characters are rational valued is called a rational group. Using the concept of transversal action, we get a sufficient condition on non Abelian rational groups that guarantees every Sylow 2-subgroup is also rational. This gives a partial answer to an old conjecture rationality of Sylow 2-subgroup of rational group.