I thought it was an interesting paper and the first post didn't get any traction.

From the FAQ: https://news.ycombinator.com/newsfaq.html

> Are reposts ok? If a story has not had significant attention in the last year or so, a small number of reposts is ok. Otherwise we bury reposts as duplicates.

Sometimes the moderators also invite users to resubmit (although this was not the case here).