那是tensor, 大家都習慣Einstein notation，愛因斯坦是懶鬼，不想每次都寫上summation符號。

來源: BeLe 於 2023-04-06 21:51:00 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.