PermGroupOps.SmallestMovedPoint( G )
PermGroupOps.SmallestMovedPoint  returns the smallest  positive integer
which   is   moved   by    the   permutation   group    G   (see   also
PermGroupOps.LargestMovedPoint).  This function signals an error if G
is trivial.
    gap> s3b := Group( (2,3), (2,3,4) );;
    gap> PermGroupOps.SmallestMovedPoint( s3b );
    2 
GAP 3.4.4