Most equivalence relations eventually drop any special notation in favor of = In general, = is not rigorous. It's used as a stand-in for the word "is". Anoth

Most equivalence relations eventually drop any special notation in favor of = In general, = is not rigorous. It's used as a stand-in for the word "is". Another example is when someone writes x = 1, ..., N, meant to imply x is changing, not that x is equal to a tuple. Also the index in summation notation, which really is an assignment as in programming. I could go on.