Sure, but that's an odd reading of GP's "graphical notations like this one". Feynman diagrams are very useful, and made respectable lots of other graphical not

Sure, but that's an odd reading of GP's "graphical notations like this one". Feynman diagrams are very useful, and made respectable lots of other graphical notations. There's a nice book on this: https://www.press.uchicago.edu/ucp/books/book/chicago/D/bo3534300.html https://www.press.uchicago.edu/ucp/books/book/chicago/D/bo35... But diagrams as a replacement for writing out tensor indices, like in TFA, which was what I presume GP meant... these have not proven widely useful. I guess people doing tensor network things use them.