Because of the interdisciplinary nature of the field, often research is undertaken without the benefit of insights from substantially similar work that has taken place either in another subfield, or that has taken place as a necessary peripheral task in a research efforts with a different focus. We found striking similarities between efforts that, as far as we can determine, were completely independent. This is not unexpected,and is in fact encouraging: often when he time comes," fundamentally identical technical advances are made simultaneously by independent groups. We hope that this survey helps to establish common ground from which future efforts
can reach even higher.