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Hi! I'm Sergio. Goog GAP to all of you :-)

I'm in trouble, of course. I can't build any relations.

I suppose that I cannot write something like:

gap> GeneralMappingByRelation(A, B, a <= b);

However, I can't understand GeneralMappingByElements(S, R, elems).

No example :-(

"elems" should be a collection of tuples; how can I build one?

How could I build a Tuple?

For example:

gap> A := [1,2,3];; gap> T := UnorderedTuples(A, 2); [ [ 1, 1 ], [ 1, 2 ], [ 1, 3 ], [ 2, 2 ], [ 2, 3 ], [ 3, 3 ] ] gap> IsCollection(T); true gap> IsTuple(T[1]); false

What?!? UnorderedTuples "returns the set of all unordered tuples of

length k of the set set." T is a collecton, but it is not a collection

of tuples. Is it? Moreover, IsTuple is not documented: there is just a

dangling reference (``badlink:ref:istuple'' in CHAP029.htm,

``see~"IsTuple"'' in mapping.tex. BTW: I'm using gap4r1 fix1).

Another try:

gap> A := [1, 2, 3];;

gap> GeneralMappingByElements(Integers, Integers, UnorderedTuples(A,

2));

Error <elms> must be a collection of tuples or empty .....

Could anybody please help me?

Thanks

---------------------------------------------------------------------- Sergio Polini "The box said 'Requires Windows 95, NT e-mail : s.polini@mclink.it or better.' So I installed Linux." PGP key: http://members.tripod.it/spolini/pgpkey.html

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