Dear GAP-Forum,
due to an error for which I unfortunately cannot blame a computer,
part of the new documentation for GAP 3.4 has not been included in the
release (while the corresponding code is included). This documentation covers:
o The library of transitive groups,
o Generic algebraic extensions of fields and
o Computation of (isomorphism types) of Galois groups.
This documentation will be included in the next patch, that is to be
released in the near future.
I apologize for this mistake. If anyone is in urgent need of the
documentation, I can provide him the corresponding files already now.
Alexander Hulpke (Alexander.Hulpke@math.rwth-aachen.de)
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In short, the new commands include:
TransitiveGroup(deg,nr);
Creates a transitive permutation group of the isomorphy type given in
Butler/McKay: the transitive groups of degree up to 11, CommAlg 11(1983),
863--911
TransitiveIdentification(grp);
if grp is a transitive permutation group of degree d<=11, then this command
yields the number of the permutation isomorphy type of grp, i.e.
grp ~= TransitiveGroup(d,TransitiveIdentification(grp)).
if f is a polynomial over the rationals, then
Galois(f);
yields the number of the isomorphism type of the corresponding Galois group.
(This might take substantial time).
ProbabilityShapes(f);
return a list of guesses for the isomorphism type of the Galois group. It is
much faster, but might be wrong.
If f is any polynomial, then
AlgebraicExtension(f);
creates the corresponding algebraic extension,
RootOf(f);
the generating element. The base field is naturally embedded.
Multiple algebraic extensions are not supported.
Polynomial factorization is possible over Algebraic extensions of finite
fields or the rationals (as well as over these ground fields themselves)\
by specifying a polynomial over this field and using 'Factor'.
Polynomial factorization over the rationals has been possible (but
undocumented) already in version 3.3, but this algorithm has been improved
significantly in 3.4.