I was referring to this: > [All NP-hard problems] have equivalent difficulty. I get what OP meant, but there can still be some NP-hard problems that are more

I was referring to this: > [All NP-hard problems] have equivalent difficulty. I get what OP meant, but there can still be some NP-hard problems that are more difficult than others. As I said, x^4 and x^10 are both polynomials. I wouldn‘t call them "equivalent" though.