[GAP Forum] NaturalHomomorphismByGenerators

Jose Joao Morais jjoao at netcabo.pt
Mon Jan 26 10:28:52 GMT 2004


Dear GAP-Forum,

	I have the following monoid:

x0:=Transformation([6,1,2,3,4,6]);
x1:=Transformation([1,2,3,5,6,6]);
x2:=Transformation([1,2,4,6,5,6]);
x3:=Transformation([1,3,6,4,5,6]);
x4:=Transformation([2,6,3,4,5,6]);
poi5:= Monoid(x0,x1,x2,x3,x4);

	Then I do:

G:=poi5;

F:=FreeMonoid(List([1..Length(GeneratorsOfMonoid(G))],
i->Concatenation("x",String(i))));


gap> h:=NaturalHomomorphismByGenerators(F,G);;
gap> ih:=InverseGeneralMapping(h);;
gap> IsInjective(ih);
true

gap> Image(ih, Elements(G)[2]);
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 2nd choice method found for `ImagesSet' on 2 arguments called from
ImagesSet( map, Source( map ) ) called from
ImagesSource( map ) called from
IsSurjective( InverseGeneralMapping( inv ) ) called from
IsMapping( map ) called from
<function>( <arguments> ) called from read-eval-loop
Entering break read-eval-print loop ...
you can 'quit;' to quit to outer loop, or
you can 'return;' to continue


	Can you tell me what is wrong with this and how can I compute de image of an element of G
through ih?

	Thank you,
	Jose Morais






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