Let be a -adic field. We give an explicit characterization of the abelian extensions of of degree by relating the coefficients of the generating polynomials of extensions of degree to the exponents of generators of the norm group . This is applied in an algorithm for the construction of class fields of degree , which yields an algorithm for the computation of class fields in general.
While most algebra is done by writing text and formulas, diagrams have always been used to present structural information clearly and concisely. Text shells are the interface for computational algebraic number theory, but they are incapable of presenting structural information graphically. We present GiANT, a newly developed graphical interface for working with number fields. GiANT offers interactive diagrams, drag-and-drop functionality, and typeset formulas.
We present an algorithm that returns a proper factor of a polynomial over the -adic integers (if is reducible over ) or returns a power basis of the ring of integers of (if is irreducible over ). Our algorithm is based on the Round Four maximal order algorithm. Experimental results show that the new algorithm is considerably faster than the Round Four algorithm.
We present an algorithm for computing the 2-group of the positive divisor classes in case the number field has exceptional dyadic places. As an application, we compute the 2-rank of the wild kernel in .
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