in my project I put all generated transactions inside a virtual ring among candidate nodes and ask them to introduce their candidate block - then other nodes could immediately see the fork(s) and wait for the result of finalizing procedure that broadcasts the confirmed block. so this bounce may just fit into that new data/proof model, not classic PoW.
Could you share more details of it?
please download the latest edition of the whitepaper that contains the proof model too:
https://bitcointalksearch.org/topic/shahin-go-round-proof-of-consistency-poco-and-the-ringchain-5066624
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and also there are pretty well defined notes about relationship of a successful selfish-mining scenario with 1) the quality of connectivity among nodes and 2) adjustment of difficulty - available here in this study:
http://www.mixoftix.net/knowledge_base/blockchain/dynamics_of_blockchain_2016.pdf
which means other samples that we had above could indirectly help preventing selfish-mining..