Maybe the categories "PCP" and "Hardness of Approximation" should be united.
Also, I think that "Hardness Amplification" should be renamed to "Average Case Complexity", so it will be able to contain more problems.
After some more thought
Maybe the categories "PCP" and "Hardness of Approximation" should be united.
Also, I think that "Hardness Amplification" should be renamed to "Average Case Complexity", so it will be able to contain more problems.