The relation between a group product and its factors is provided via homomorphisms, the embeddings in the product and the projections from the product. Depending on the kind of product only some of these are defined.
Embedding(P,nr) O
returns the nr-th embedding in the group product P. The actual meaning of this embedding is described in the section for the appropriate product.
Projection(P[,nr]) O
returns the (nr-th) projection of the group product P. The actual meaning of the projection returned is described in the section for the appropriate product.
GAP 4 manual