As Y. N. Moschovakis says, however, this is mostly an exercise in mathematical elegance, and you don't gain much unless you are "allergic to subscripts."
不過，如 Y. N. Moschovakis 所说，这只是作為體現数学簡潔性的一个練習，你不会得到更多东西除非你“对下标过敏”。