add_rel! and quotientgroup for the future

src/FPGroups.jl

@@ -105,3 +105,21 @@ function add_rel!{T<:FPSymbol}(G::FPGroup, w::GWord{T})
 end
 
 end #of module FinitelyPresentedGroups
+# function add_rel!{T<:FPSymbol}(G::FPGroup, w::GWord{T})
+#    if !(w in G.rels)
+#       w = G(w)
+#       push!(G.rels, w)
+#    end
+#    return G
+# end
+#
+# function quotientgroup(G::FPGroup, rels::Vector{FPGroupElem})
+#    for r in rels
+#       parent(r) == G || throw("Can not form quotient group: $r is not an element of $G")
+#    end
+#    H = deepcopy(G)
+#    for rel in rels
+#       add_rel!(H, rel)
+#    end
+#    return H
+# end