mathlib3

cfc74155 - feat(field_theory/polynomial_galois_group): Galois group is S_p (#7352)

feat(field_theory/polynomial_galois_group): Galois group is S_p (#7352) Proves that a Galois group is isomorphic to S_p, under certain conditions. Co-authored-by: tb65536 <tb65536@users.noreply.github.com>