SPECTRE: Serialization of Proof-of-Work Events, Confirming Transactions via Recursive Elections. A Fast and Scalable Distributed Ledger Protocol (by Yoad Lewenberg, Yonatan Sompolinsky, and Aviv Zohar) https://medium.com/@avivzohar/the-spectre-protocol-7dbbebb707b5#.maypst90g Is this the same DAG protocol iota uses?