diff --git a/src/FPGroups.jl b/src/FPGroups.jl
index 65e1bbd..642c40b 100644
--- a/src/FPGroups.jl
+++ b/src/FPGroups.jl
@@ -54,6 +54,14 @@ end
 (G::FPGroup)(s::FPSymbol) = G(FPGroupElem(s))
 
 
+hash(s::FPSymbol, h::UInt) = hash(s.str, hash(s.pow, hash(FPSymbol, h)))
+
+isone(s::FPSymbol) = s.pow == 0
+
+change_pow(s::FPSymbol, n::Int) = FPSymbol(s.str, n)
+
+length(s::FPSymbol) = abs(s.pow)
+
 function show(io::IO, G::FPGroup)
     print(io, "Finitely presented group on $(length(G.gens)) gens and $(length(G.rels)) relations:\n")
     print(io, "gens:\t", join([g.gen for g in G.gens], ","),"\n")