Thus the secret chain can end up the longest chain without needing 50% of the hashrate.
This can never happen because the chain length is sum of difficulty not block count, although with some probability you might have a slightly lower hash rate and still get lucky and win more than half of the (weighted) blocks, as usual.
I agree if the comparison of two forks is the sum of the modular additive inverses of the block hashes.
In
my prior post, I was trying to figure out how it was possible that the secret chain could be "longer" when it has less hashrate. Originally I didn't think it was possible, which is why I ignored the ideas from that thread and had presented other ideas further upthread. Then I reread that thread again.
Perhaps Auroracoin had a bug in that it only compared # of blocks? Or as you say Nite69 seemed to not know what he was talking about. That is what I originally wrote in my prior post, then just before I posted it I changed it because I guess I got confused in my haste as I was trying to figure what the heck those guys (Nite69 et all) were describing.