42.18 MappingByFunction

MappingByFunction( D, E, fun )

MappingByFunction returns a mapping map with source D and range E such that each element d of D is mapped to the element fun(d), where fun is a GAP function.

    gap> g := Group( (1,2,3,4), (1,2) );;  g.name := "g";;
    gap> m := MappingByFunction( g, g, x -> x^2 );
    MappingByFunction( g, g, function ( x )
        return x ^ 2;
    end )
    gap> (1,2,3) ^ m;
    (1,3,2)
    gap> IsHomomorphism( m );
    false 

MappingByFunction constructs the mapping in the obvious way. For example the image of an element under map is simply computed by applying fun to the element.

Previous Up Top Next
Index