Hervé Pagès wrote: [...] > > So in fact, the following is true for any Bimap object 'x': > > length(unique(toTable(x)[[2]])) == count.mappedkeys(x) # always TRUE oops, the correct equalities are: length(unique(toTable(x)[[1]])) == count.mappedLkeys(x) # always TRUE length(unique(toTable(x)[[2]])) == count.mappedRkeys(x) # always TRUE sorry H.