For instance, if and then is a rupture field for .
The notion is interesting mainly if is irreducible over . In that case, all rupture fields of over are isomorphic, non canonically, to : if where is a root of , then the ring homomorphism defined by for all and is an isomorphism. Also, in this case the degree of the extension equals the degree of .
A rupture field of a polynomial does not necessarily contain all the roots of that polynomial: in the above example the field does not contain the other two (complex) roots of (namely and where is a primitive third root of unity). For a field containing all the roots of a polynomial, see the splitting field.