Rupture field

In abstract algebra, a rupture field of a polynomial over a given field such that is a field extension of generated by a root of .[1]

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.

Examples

A rupture field of over is . It is also a splitting field.

The rupture field of over is since there is no element of with square equal to (and all quadratic extensions of are isomorphic to ).

See also

References

  1. Escofier, Jean-Paul (2001). Galois Theory. Springer. p. 62. ISBN 0-387-98765-7.
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