Oh but in J loops exist, they are mostly implicit in the operation. So it is not “loopless” per se, as the sigma notation for summation indicates a loop in a s

Oh but in J loops exist, they are mostly implicit in the operation. So it is not “loopless” per se, as the sigma notation for summation indicates a loop in a single construct, and it “can be written away” using Einstein’s notation. That is how it should be understood, imo.