not really. it's one of the most difficult ones so far for sure, but pales in comparison to something like the classification of finite simple groups. This was

not really. it's one of the most difficult ones so far for sure, but pales in comparison to something like the classification of finite simple groups. This was initially "completed" in the 80s. You can see the timeline for cleaning up the proof in e.g. this mathoverflow answer https://mathoverflow.net/questions/114943/where-are-the-second-and-third-generation-proofs-of-the-classification-of-fin/217397#217397 https://mathoverflow.net/questions/114943/where-are-the-seco... it's something that some people have been waiting decades for, and is not yet completed.