Voters: please reconsider your ups and downs. I think the “Are you an expert” question triggered a lot of downvotes when it was in fact asked in good faith to judge the person’s perspective of easy and hard.
The correct question would have been, does anyone else agree with the statement.
In this particular case, the amount knowledge needed (of e.g. Lean language, math and Erdos problems) means any credible statement about the difficulty requires an expert.
Like if someone were incredulous that we could reasonably analyze running time and memory usage of something like merge sort and I said that's a standard example in an intro algorithms course, presumably people would be like "yeah it is".