As indicated in section Mathematical Introduction, the relators and
subgroup generators are specified as elements of the free product,
K*F_X which is to say products of elements of K and generators from
X (and their inverses). These are represented in GAP as DCE Words,
created using the DCEWord function. This is called as DCEWord(K, l)
where l is an element of K, a word in abstract generators or a list
of these. DCE Words are in GroupElements and can be multiplied (when
the groups K match), inverted, raised to powers and so forth.
Note that the abstract generators are used here simply as
place-holders. Although, in general, creating abstract generators with
AbstractGenerator rather than FreeGroup is a bad idea, it will not
cause problems here. A new version of this package will be produced for
GAP 4 which will avoid this problem.
GAP 3.4.4